Japan on the Path to World War Two
The causes of the Japanese-Allied conflict
author Paul Boșcu, January 2019
The path that led Japan on one side, and the United States, China and Britain on the other to war is long and complex. The origins of the conflict can be identified in Japan's unique history and culture, nurtured by the expansionist tendencies of its leaders in the 1930's.
The Pacific War was caused by the expansionist ambitions of Imperial Japan. The chain of events that led to it can be described fairly easily. It is much harder to explain why Japan initiated a war against the one country that had the power to defeat it: the USA. The answer is perhaps found in Japan's unique culture and history. Having not experienced defeat for a thousand years, and believing in the superiority of their culture and spirit, the Japanese could not conceive of defeat. Somehow, trusting in the living-god Emperor, they would win, even if many would die in the process.

If Japan were to survive, it had to establish a powerful and modern army, and a capable navy, and to support these forces it had to begin a rapid process of industrialization. Lacking natural resources but possessing a large, industrious population, Japan had to secure supplies of raw materials and find markets for its goods.

In 1937 Japan was a strong, technologically advanced nation with a population of 70 million. During the 1930s its open, market-oriented economy had been transformed into a directed war economy, but it weakness was its heavy dependence on overseas supplies of oil, raw materials, and rice.

Any comparison of the military and industrial strengths of the Japanese Empire and the Allies must conclude that Japan had no chance of winning. While Japan could deploy more than a million soldiers, three of its enemies could do likewise. And while Japan possessed the world's third largest navy, it was opposed by the even stronger American and British navies. Yet Japan began the war with considerable advantages.

Japan’s military leaders made their critical commitment in 1937, when they embarked upon the conquest of China. This provoked widespread international hostility, and proved a strategic error of the first magnitude. Amid the vastness of the country, their military successes and seizures of territory were meaningless. A despairing Japanese soldier scrawled on the wall of a wrecked building: ‘Fighting and death everywhere and now I am also wounded. China is limitless and we are like drops of water in an ocean. There is no purpose in this war. I shall never see my home again.’

By seizing the initiative, Japan severely damaged the US Pacific Fleet at Pearl Harbor, eliminated the dangerous US bombing force in the Philippines, and threw the British forces in Malaya off-balance. Once the USA lost its western Pacific bases, it had to cross thousands of miles of ocean to take the fight to the Japanese. The USA also had to divide its forces between the European and Pacific theaters. To an even greater extent, Britain concentrated on Europe, and it could not deploy its naval strength fully until the last year of the war.

The geographic spread of operations across the maritime areas of the Pacific meant that air and naval forces played a major role. It was here that the industrial strength of the USA gave the Allies a significant advantage. In fact, by the end of the war, the US navy in the Pacific was the largest in history. Once the Allies could apply their naval and air strength to the fullest extent, their final victory was inevitable.

The origins of the war lie in Japan's emergence after more than two centuries of isolation from the outside world. To protect itself from foreign influences, in the early seventeenth century Japan had expelled all foreigners and had severely restricted foreign access to the country. This isolation was shattered in 1853, when four American warships appeared in Tokyo Bay and their commander, Commodore Matthew Perry, began negotiations that led eventually to a commercial treaty between the USA and Japan.

At the beginning of the Meiji Restoration in 1867–68, the Emperor Meiji, re-empowered, pledged himself to restore Japanese self-respect. Two recent experiences had created the Japanese sense of military inferiority: the entry of a US Navy squadron into Tokyo Bay in 1854 and the Royal Navy’s bombardment of Kagoshima and Shimonoseki in 1862-63 in retaliation for the mistreatment of Western nationals.

After the end of the period of isolation, the Japanese moved rapidly to modernize their country. The power of the feudal warlords collapsed and in 1868 the new Emperor announced a policy of seeking knowledge from around the world. Japan adopted a vaguely democratic constitution with an elected parliament or Diet. Compulsory education was introduced, although with heavy emphasis on obedience to the Emperor. The Japanese wanted European technology and expertise, but did not have the time or the inclination to absorb Western ideas of democracy or liberalism.

The Japanese were acutely conscious of their vulnerability. Over the preceding centuries, European powers had seized colonies in the Asia-Pacific area. Britain held Malaya, Burma and India, the French were in Indo-China, the Dutch owned the East Indies (now Indonesia) and Germany had part of New Guinea. The Europeans and the Americans had also won concessions from a weak and disorganized China.

By the end of the century, the modernized Japanese Army and Navy looked Europeanized in matters of uniforms and weapons, but the soul of the armed forces remained rooted in the samurai tradition of Japanese feudalism.

The Japanese observed that the European powers had gained economically by exploiting their military and diplomatic power in Asia. Taking this lead, Japan initiated a short and successful war with China over access to Korea, at the end of which China ceded Formosa (Taiwan) and the Liaotung peninsula in southern Manchuria, which included the fine harbor of Port Arthur. Under pressure from Russia, Germany and France, Japan was forced to withdraw from Manchuria. Russia moved into Manchuria, while Germany and France grabbed further concessions in China. To the enraged Japanese, it seemed that there was one rule for the European powers and a different rule for Asian countries. Three years later, the USA took control of the Philippines.

Japan defeated its only Asian rival, China of the Ch’ing Dynasty, in a naval campaign marked by surprise and the full exploitation of modern warships. A land campaign in Korea and Manchuria proved that German-made weapons and the Japanese warrior spirit could produce impressive victories.

The Japanese were determined to gain control of the areas they saw as vital to their economic survival. In 1904 Japan blockaded Port Arthur, and moved troops into Korea and Manchuria. In a bloody war with heavy casualties on both sides, the Japanese defeated the Russian army in Manchuria and destroyed the Russian fleet sent to relieve Port Arthur. Japan took control of the Liaotung peninsula and stationed troops to protect the Manchurian railroad. By 1910, Japan had annexed Korea. For the first time, an Asian power had defeated a European power, and the Japanese army gained in prestige and strength.

The twin victories against China and Russia brought Formosa and Korea under Japanese rule and opened Manchuria to economic exploitation under the protection of resident Japanese soldiers. Participation in the suppression of the Boxer Uprising also produced concessions and privileges for Japan within China.

Japan obtained tremendous advantages from the First World War. Being on the winning side, it seized Germany's possessions in China and the Pacific, but never sent land forces to Europe. Fueled by the demands of the war, Japanese industries continued to expand and Japan built up its merchant navy. In the postwar settlement, Japan retained the former German Pacific colonies under a mandate from the League of Nations. At the same time, Japan was confirmed as a principal power in the Pacific, but was viewed with suspicion by both the USA and Britain.

In part because of an alliance with Britain signed in 1902, Japan attacked and captured the German leaseholds in China. Some Japanese officials and part of the public supported Sun Yat-sen’s revolutionary movement in China, but Japan assumed that its interests called for a new policy toward its giant neighbor, a policy of anti-European hegemony that challenged the Open Door policy of the United States, which argued against special concessions to all nations.

Without heeding European cautions and the prudent counsel of some of its own political elite, the Japanese government rejected an Allied proposal that Germany’s China concessions now revert to China. Instead, Japan presented its Twenty-One Demands. Basically, the demands would have made China a protectorate and ceded direct control of the German concessions and much of Manchuria to Japanese domination. Bolstered by American support, the Chinese refused the demands for much of 1915, but finally agreed to enlarge Japanese privileges in Manchuria in exchange for protection in China proper.

The settlement for Manchuria led to acute Japanese interest in the Russian Revolution of 1917 and the fate of Siberia and Russia’s Maritime Province, anchored at Vladivostok on the Sea of Japan. Under cover of an Allied military expedition to Siberia to save the Russian war effort, the Japanese sent 72,000 soldiers deep into Asian Russia, principally to ensure that neither the Allies nor the Bolsheviks restored Russian military power. The Japanese also occupied the southern half of Sakhalin Island. Once again, Western political pressure during the World War I peace negotiations forced the Japanese to leave Siberia, but not South Sakhalin.

At a conference in Washington, the USA, Britain and Japan agreed to limit their capital ships according to a ratio of 5:5:3. The USA and Britain undertook not to fortify their Pacific possessions. Japan was aggrieved at apparent restrictions to its navy, but as both Britain and the USA also deployed their forces in the Atlantic, Japan was left as the most powerful navy in the western Pacific. Still suspicious of Japan, in 1923 Britain decided to establish a naval base at Singapore, to which it would send its main fleet in time of crisis in the Pacific.

Japanese diplomats journeyed to Washington, D.C., to demonstrate their nation’s new-found sense of international responsibility by agreeing to three treaties designed to stabilize the status quo in Asia. The Five Power Treaty (Japan, Britain, France, Italy and the United States) put a ceiling on the building and modernization of large warships. The Four Power Treaty pledged the signatories (Japan, Britain, France and the United States) not to attack one another’s colonies. The Nine Power Treaty (including Japan) placed China off-limits for further imperialism.

Manchuria’s status underwent no major change, which meant that several nations and international business consortiums retained special privileges. Another important aspect of the Washington treaties was that they freed Britain from its 1902 treaty with Japan.

The Japanese economy and society were coming under great strain. During the 1920s, numerous earthquakes shattered cities and factories. The largest struck Tokyo in 1923. As the world economic system began to falter, Western countries applied trade restrictions that hurt Japanese industries. The Great Depression is generally thought to have begun with the Wall Street crash in 1929, but by 1926 more than three million Japanese industrial workers had lost their jobs. The Japanese government came under increasing pressure from militant nationalist groups, often led by young army officers. This was a similar environment to that which led to the rise of Nazism in Germany, fascism in Italy and communism in various countries.

Like the citizens of the United States and Western Europe, the Japanese people themselves sought ‘normalcy’ in the 1920s, which meant reductions in military spending, an abatement of hostility to the West, and an improvement of economic conditions through trade and internal agricultural and industrial production. Despite the influence of Confucianism, Shintoism - a state religion of ancestor and emperor worship - and Germanized corporations and universities, the urban Japanese population showed serious interest in life, liberty, and the pursuit of family happiness.

The Japanese Diet, a pale copy of Western assemblies, suddenly showed new courage in the 1920s and backed the appointed courtiers in the cabinet against the militarist-expansionists. Military officers still enjoyed inordinate prestige, but for a moment the cautious conservatives — an alliance of court nobility and Westernized technocrats — persuaded the successive cabinets to pursue an international policy of cooperation rather than confrontation. The ‘peace party’ profited by the death in 1922 of Prince and Field Marshal Yamagata Aritomo, whose power in the army and in the court made him a cabinet maker and breaker.

Although the international treaties signed in Washington slowed Japanese expansionism in the 1920s, the countervailing winds of domestic politics created conditions for a resurgence of Japanese ‘manifest destiny’ in the 1930s. Instead of a government dominated by clan representatives, the cabinets of the 1920s represented an uneasy and inherently unstable coalition of conservative courtiers, senior military officers, industrial moguls or zaibatsu, and a new group of party politicians and bureaucratic technocrats. The political parties, except for the socialists, were weak and riven by corruption and personal feuds and enjoyed no special public appeal.

The liberalization of political participation in the 1920s created a politicized urban middle class that proved easy to agitate and manipulate through the schools, media, and government bureaucracy. Alarmed by the prospect of democratic reform, the Diet passed the Peace Preservation Act of 1925. This imposed ten years’ imprisonment on those who joined societies seeking to alter the government or challenge private property rights. With little imagination, such an act could be extended to any dissident political group.

After subduing Japanese imperialism through the Washington treaties, the governments of the United States, Britain, and the European states with Asian interests regarded Japan as a fully-fledged member of the international community, as a signatory of the League of Nations agreement, and as a global trading partner. Its lack of natural resources except coal meant that it had to remain a supplicant in the international trading order of the 1920s, still only a protégé of Britain and the United States. Westerners, especially the British and Americans, tended to exaggerate their influence on Japanese culture and to underestimate the latent hostility in Japan towards Western civilization.

The only Western export that the Japanese truly respected was industrial technology, particularly the rate at which Western factories spewed forth durable goods. More for reasons of national power than private consumption, Japan plunged into the interdependent world of commerce and resource competition with the ardor of a new convert. Like Britain, its Western model, Japan moved quickly towards industrialization.

Christian missionaries in particular almost always exaggerated the impact of Western religion in Japan. Fewer than one percent of the population showed even passing interest in Christianity. Often ‘interested’ Japanese were simply looking for a good way to learn English and to gain entry into prestigious universities in the United States and England. Western popular culture on the other hand — music, sports, and films — fascinated the Japanese, but it did not transform them.

British and American attitudes towards the Japanese still reflected traditional anti-Asian racism. Foreigners perceived industrial progress in Japan as merely copying European practices — reverse engineering of the grandest sort to which the Japanese added no originality. Westerners often overlooked the Japanese research and development strategy, which was to catch up with the West as fast as possible and then innovate where opportunities arose for real product improvements, such as the Zero fighter aircraft.

Unlike Britain, Japan had no empire from which to draw cheap raw materials. Formosa and Korea hardly gave Japan autarky. Its special privileges in Manchuria did not suffice. By the 1930s Japanese politicians saw the economic exploitation of China as Japan’s only salvation from economic retreat. When its economy swooned in the 1930s, Japan chafed under the economic barriers it faced in Asia. The colonial status of South East Asia limited Japanese access to these markets. The hostility of Britain, the United States and the Soviet Union toward Japanese economic penetration in Manchuria and China seemed to embody imperialist discrimination, if not outright hypocrisy.

The Soviet Union had replaced Germany as the patron of Chiang Kai-shek’s Nationalist Chinese government, based at Nanking, even though the Nationalists had driven the Chinese Communists into northwestern China in 1931. The Japanese looked on with alarm as the Soviet-Chinese relationship warmed in the 1930s, and the prospect of greater military collaboration between the two powers grew.

The American position was the most incomprehensible to the Japanese. The Americans had never shown the same exploitative ardor in China as the Europeans had; their attachment appeared to be more a matter of sentiment and cultural imperialism. American investment and trade with Japan was at least five or six times greater than with China. In the end, Japanese officials thought, American economic sanity would prevail, and the United States would accept Japan’s need to dominate China’s economy.

The Americans and their interests were harder to understand than the Europeans, who seemed ready to police their colonies with a hard hand. The American Congress, by contrast, passed legislation in 1934 that promised Philippine independence a decade later; the Roosevelt administration allowed a retired army chief of staff, Douglas MacArthur, to go to Manila to start a Filipino national army — to recreate the very army that an American army had crushed 35 years before.

The Soviet approach was straightforward and consistent: Western imperialism in Asia should fall to the revolt of the oppressed masses. The Japanese, who had supported Asian revolutionaries before the rise of Communism in the 1920s, watched the growth of subversive undergrounds in Indochina and the Dutch East Indies, convinced that they could exploit the coming collapse of European imperialism.

The United States maintained regular forces in the Philippines around Manila Bay that could not by themselves defeat a determined invasion. But Congress was unlikely to invest military money in a non-white colony that it yearned to detach from the American flag. In China, the United States maintained troops in Shanghai, Tientsin, and Peiping to pressure the Europeans to surrender their special privileges and trading rights.

In Manchuria and northern China, Japan was facing new challenges. In China, nationalist forces were being consolidated under Chiang Kai-shek. The Japanese semi-autonomous Kwantung Army, policing the Manchurian railroad, was a highly political organization that attracted the best and most ambitious Japanese officers. Officers of the Kwantung Army falsely accused the Chinese of sabotaging the Port Arthur-Mukden railroad. Against the wishes of the government, Japanese forces attacked the armies of the local Chinese warlords and quickly overran Manchuria. Powerless, the Japanese government acquiesced, and the following year Japan established a puppet state - Manchukuo.

This so-called Manchurian Incident marked the beginning of full-scale Japanese aggression in Asia. The US Secretary of State condemned Japan, and after an investigation the League of Nations branded Japan as the aggressor. In response, in March 1933 Japan withdrew from the League of Nations. The Japanese War Minister, General Araki Sadao, complained that the League of Nations did not respect Japan's 'holy mission' to establish peace in the Orient, but vowed that the day would come when 'we will make the world look up to our national virtues'.

The army kidnapped Henry Pu Yi, the last Ch’ing emperor, from Tientsin and installed him as the emperor of Manchukuo, a puppet state. To preempt Chinese intervention, the Kwantung Army attacked Chinese garrisons in northern China and Mongolia between 1931 and 1935, despite a League of Nations resolution (without sanctions) disapproving Japanese aggression. Neither the United States nor Britain took action, while the Soviets sold their railroad interests in Manchuria and retreated to the north.

The army, as the principal administrative arm of the government in Manchuria and Korea, developed not just autonomy abroad but the political power that could bring down cabinets in Tokyo. So great became the influence of the Kwantung Army in Manchuria that a clique of its officers could shape Japanese policy.

Some Japanese officers saw Manchuria as the essential first step towards a larger plan to conquer China: a secure base in Manchuria would provide industrial raw materials and food, and would check Soviet military assistance to either the Chinese Nationalists or Communists.

Staged demolitions in Mukden and elsewhere preceded a rapid Japanese occupation of key political and economic sites, the disarming or routing of Chinese soldiers and police, and a rush of reinforcements from the Japanese Army in Korea and its Korean auxiliaries. Key conspirators in Tokyo blocked ministerial action until the occupation neared completion; army officers at the Imperial General Headquarters blessed the ‘incident’ after the fact and helped bring down the cabinet.

The Japanese waged a harsh, bloody, punitive campaign in Shanghai in 1932 in retaliation for anti-Japanese actions and riots in that port. The Chinese Army fought with considerable effectiveness, and the Japanese found themselves hard-pressed to drive the Chinese from the city. Only by using a marine brigade and three army divisions were they able to defeat the Nineteenth Route Army, which was trained and armed by German and Soviet advisers. In the meantime, the Japanese withdrew from the League of Nations and renounced the three Washington treaties it signed in 1921.

The growing tumult in China encouraged the division and radicalization of the Japanese Army’s officer corps, where one group of senior officers, labeled by their opponents as Toseiha or the Control Clique, committed themselves to the cause of expansionism in China. The other faction, which had begun in the 1920s as the Young Officers Movement, urged caution abroad and revolution at home, a rejection of Western materialism and capitalism, the leveling of social classes, and a return to a dictatorial emperorship that would exalt traditional Japanese values.

Despite these belligerent actions, the Japanese government was actually in disarray. In November 1930 the Japanese Prime Minister was gunned down for accepting allegedly humiliating conditions at a naval conference in London. In February 1932 two leading politicians were assassinated by members of the Blood Brotherhood - modern day samurai warriors who were prepared to sacrifice themselves for the good of Japan. In May 1932 they murdered the new Prime Minister for criticizing Japanese aggression in Manchuria. In February 1936 radical army officers attempted a coup d'etat, murdering several leading government ministers. The coup attempt failed, but the army gained even more power.

The Cherry Society of dissident officers, founded in 1930, sought to change Japan through military revolution; their status in the army effectively protected them from the Peace Preservation Act. The Cherry Society cultivated political violence and influenced the murders of Prime Ministers Hamaguchi Yuko in 1930 and Inukai Ki in 1932.

In 1937 the War Minister (a serving army officer) submitted a bill to parliament to give the government absolute control over industry, labor and the press. The Diet meekly voted its approval. Also the government initiated a plan to expand its heavy industries to enable it to wage a total war for three years, and it stepped up the naval building program. In November 1936 the army had negotiated the Anti-Comintern Pact with Germany and Italy. It was directed squarely against the Soviet Union, which was supporting China.

In an act of gekokujo (principled indiscipline) staged in 1936 - the so-called Two-Twenty-Six Incident - 1,400 Kodoha officers and soldiers attempted to kill three key Court officials, two senior cabinet ministers, and the respected inspector-general of training. Their plans to seize government and army buildings failed, and the mutineer officers soon saw their troops abandon them. In crushing the coup, Control officers, including such expansionist missionaries as Major General Ishiwara Kanji and Major General Doihara Kenji, known for his special operations as Lawrence of Manchuria, moved into key planning billets.

Even with reduced budgets, the Imperial Japanese Army (IJA) and Imperial Japanese Navy (IJN) retained a hard grip on the lives of the Japanese people. Conscription continued after World War I, and the school system demanded reverence for the Emperor and the armed forces. As the army and navy modernized some of their weapons, especially aircraft, they developed strong working ties with the zaibatsu, the Japanese industrial moguls.

One faction within the Young Officers Movement called Kodoha or the Imperial Way Group, became the shooting edge of political extremism in Japan. It played a role in six army mutinies and acts of political terrorism in Japan between 1931 and 1935. The Control faction, led by General Nagata Tetsuzan, started a purge of the army’s key billets that would eliminate 3,500 Kodoha oppositionists, including the Kodoha hero General Araki Sadao, who was removed from his post as Minister of War. Enraged, a Kodoha officer assassinated Nagata in August 1935.

Although the general staff in Tokyo wanted to avoid war if possible, the Kwantung Army in Manchuria had its own vision of Japan’s future. As explained by General Tojo, the dour military policeman whose control of the Kwantung Army during the Two-Twenty-Six Incident had made him its chief of staff, that plan included moving against the north Chinese warlords before they joined the Nationalists. Kwantung Army leaders also warned Tokyo about another alliance between the Nationalists and Communists.

A mature, forceful Emperor might have rallied the peace party coalition and controlled the military, but the slight, bespectacled Hirohito, who became Emperor in 1926 at the age of twenty-five, accepted his traditional non-activist role. He entitled his reign showa or ‘enlightened peace’. However, his first twenty years of rule proved neither enlightened nor peaceful. Much influenced by British culture, Hirohito valued most of all his role as reigning monarch. Although his power was theoretically absolute, his real power remained limited, but real enough.

When the army and navy in 1936 sought his approval for planning wars against China and Russia (the ‘continental strategy’) and against the Europeans in Southeast Asia (the ‘move south strategy’), he approved both. Perhaps the Emperor supposed that inter-service rivalry and internal factionalism within both the army and navy officers’ corps would produce stalemate. If so, he badly misjudged his generals and admirals.

The limited Japanese military operations in northern China brought no serious European intervention, not even from the Soviet Union. The diplomats dithered, but the consensus from Europe, alarmed by Hitler’s annexation of Austria, was that the United States should assume principal responsibility for policing Japan. Congressional and public isolationism made it difficult for Roosevelt to assist China, even by halting the flow of oil, scrap iron, and strategic metals to Japan. The United States had no taste for a confrontation over distant Asian lands.

The US Department of State had an articulate faction of Sinophiles, but they could not overcome Secretary of State Cordell Hull’s fear of war with Japan or the arguments of the Europeanists that a confrontation in the Pacific would only deepen the growing political crisis in Europe.

Japan did little to mask its intention to revise the international system, but its recurring political upheaval at home and growing military pressure against the warlords of northern China brought no American response except the ‘moral protest’ of not recognizing the puppet regimes in Manchuria and the contested Mongol provinces.

On the night of 7 July 1937, shots were fired at a Japanese detachment on maneuvers a few miles from Peking. Japanese and Chinese forces had engaged in frequent skirmishes during the previous six years, but this time the Nationalist Chinese leader, Chiang Kai-shek, believed that he could no longer tolerate Japanese provocation. To some historians the 'China Incident', as the Japanese called it, marks the true beginning of the Second World War. China and Japan were to remain at war until 1945. Over the following months the Japanese would take Shanghai and the Chinese nationalist capital, Nanking.

Nationalist Chinese planes struck Japanese warships at Shanghai. The Japanese deployed 10 divisions to northern China and five to Shanghai. When, in October, President Roosevelt finally condemned Japan's aggression, a leading Japanese, Matsuoka Yosuke, soon to be Foreign Minister, retorted: 'Japan is expanding and what country in its expansion era has ever failed to be trying to its neighbours?'

Japanese planes and shore batteries sank an American gunboat, USS Panay, which was evacuating diplomatic staff from Nanking. The American government chose to accept a Japanese apology. Nonetheless, Western observers in China, many of them American missionaries, publicized stories of Japanese atrocities. As such, the American government gradually sought ways to assist the Nationalist Chinese.

The Japanese army drove the Chinese out of Shanghai and the following month took the Nationalist capital, Nanking, where it engaged in an orgy of killing, rape, and looting. Up to 300,000 civilians may have been killed at Nanking.

Western perceptions of the war with Japan are dominated by the Pacific and South-East Asian campaigns. Yet China, and Tokyo’s refusal to abandon its ambitions there, was central to Japan’s ultimate failure. Between 1937 and 1939, major fighting took place, largely unrecognized in the West, in which Japanese forces prevailed, but with heavy losses.

Thrusting deeper into China, by the end of 1938 Japan had captured large areas of northern China, the Yangtze valley, and pockets along the coast. Chiang Kai-shek withdrew his government to the inland city of Chungking and tried to come to a cooperative arrangement with the Chinese Communists under Mao Tse-tung. The Communists conducted guerrilla warfare against the Japanese, who had established a puppet Chinese government in their area of occupation. Meanwhile, the Nationalist Chinese were working hard to win American support.

The Japanese now faced a dilemma. They could not conquer all of China, but the war was a heavy drain on their resources. Japanese army leaders hoped to resolve the war in China so that they could deal with their principal enemy, the Soviet Union. But to conclude the war, Japan needed fuel and other resources from south-east Asia. If Western countries would not supply this fuel then Japan would have to seize it. The Japanese navy leaders realized that expansion to the south would bring war, with the USA as their principal enemy. Japan now stepped up preparations for a major war.

Though the Japanese dominated the China war against the ill-equipped armies of Generalissimo Chiang Kai-shek, they suffered debilitating attrition: 185,000 dead by the end of 1941. Even a huge deployment of manpower – a million Japanese soldiers remained in China until 1945 – proved unable to force a decisive outcome upon either Chiang’s Nationalists or the communists of Mao Zedong, whose forces they confronted and sometimes engaged across a front of 2,000 miles.

Skirmishes between the Japanese and Russian armies on their common border dividing Manchuria from Mongolia erupted into full-scale war, commonly known as the Nomonhan Incident. Tokyo judged the Russians to be weak and vulnerable, and committed an army to test their resolve. The outcome was a disaster for the Japanese. General Georgy Zhukov launched a counter-offensive, supported by powerful armored and air forces, which achieved a comprehensive victory. Peace was restored on Moscow’s terms.

Soviet support for the Chinese precipitated several clashes between the Kwantung Army and Soviet forces. Finally, the Kwantung Army crossed into Mongolia. A Soviet army mounted a counter-offensive near Nomonhan that killed more than 18,000 Japanese troops. In the midst of this campaign, the Japanese were shocked to learn of the Nazi-Soviet Pact. They quickly arranged a ceasefire in Manchuria.

The strategic consequences of this conflict were important to the course of the Second World War: the Japanese army set its face against the ‘strike north’ policy, flinching from renewed conflict with the Soviet Union. In 1941 Tokyo signed a neutrality pact with Moscow. Most of Japan’s leaders favored honoring this, believing that the Western empires in South-East Asia offered softer targets for national expansion. They expected Germany to win the war in Europe.

Bogged down in China and checked by the Soviet Union, the Japanese were unsure of their next step. Then, in September 1939 Germany invaded Poland, and Britain and France declared war on Germany. The German invasion of France in May 1940 suddenly offered Japan new opportunities to cut China's overseas supplies. Chased out of Europe and hammered from the air, Britain was not strong enough to resist Japan's demand to close the road from Rangoon in Burma to Chungking, which was supplying the Nationalist government with vital supplies. Nor could the Vichy French government, formed after the German occupation, resist demands to close the port of Haiphong and give access to bases in northern Vietnam from which Japanese planes could attack southern China.

The German occupation of France also spurred the Americans into action. In May 1940 the Americans decided to station their Pacific Fleet at Hawaii and the following month they began a large naval expansion program so that their navy could operate in both the Atlantic and Pacific Oceans. In September the US Congress agreed to a peacetime draft, and in December it made $100 million in credit available to the Chinese Nationalist government. The Japanese imperial navy reacted by ordering a full mobilization - a process that would be completed by December 1941.

The fall of France indicated that more drastic measures might be necessary to lend direct assistance to Britain and to keep Southeast Asia’s resources out of Japanese hands. Roosevelt persuaded Congress to start the revision of the Neutrality Acts, if only because the administration might strengthen its hemispheric defenses by cooperating with the Allies. Although passed principally to assist the British, the Lend-Lease Act of March 1941 allowed the Roosevelt administration to consider direct military assistance to Chiang Kai-shek, whose continued resistance was helping to pin down the Japanese Army in China and away from Southeast Asia.

By the second half of 1940, war between Japan, the USA and Britain had become increasingly likely. Britain, the USA (concerned for the security of the Philippines), Australia and the Netherlands considered defensive plans in south-east Asia. Belatedly, Britain built up its garrison in Malaya and Singapore with British, Indian, and Australian troops. But preoccupied by events in Europe and the Middle East, Britain did not give the defense of Malaya high priority. The German attack on Russia in June 1941 changed the situation. Japan could either fall on Russia's Far East empire while Russia was fighting for its life in Europe or it could continue its southern expansion, secure in the knowledge that Russia would be too preoccupied to attack in Manchuria. Japan decided to strike south.

Internal Japanese politics played a crucial role in shaping the events that led to war in December 1941. The most fanatical member of the government was the Foreign Minister, Yōsuke Matsuoka, who, after Germany attacked Russia, wanted Japan also to attack Russia. He could not persuade his colleagues and so they decided to seize bases in southern Indochina. The Japanese Prime Minister, Fumimaro Konoye, dropped Matsuoka from the Cabinet, but the Cabinet still could not agree on the extent to which it should pursue negotiations with the Americans.

The War Minister, General Hideki Tojo, was pessimistic about the outcome of negotiations and was adamant that Japan had to go to war before the end of the year, when tropical monsoons would make operations difficult. Konoye wanted to negotiate for as long as possible. All agreed, however, that Japan could not withdraw from China.

The Tripartite Pact signed in Berlin between Germany, Italy and Japan promised mutual assistance if any of the parties was attacked by a nation not engaged in the European war. This was a move designed to deter the United States from exerting further pressure on Japan, and it failed. The US, implacably hostile to Japanese imperialism in China, imposed further sanctions. In response, the Japanese committed themselves to execute the ‘strike south’ strategy. They prepared to seize the West’s ill-defended south-east possessions in a series of lightning operations, bludgeoning America into acquiescence by evicting its forces from the western Pacific.

Germany and Japan never seriously coordinated strategy or objectives, partly because they had few in common beyond defeat of the Allies, and partly because they were geographically remote from each other. It is just possible that, if Japan had struck west into Russia soon after the German invasion, such a blow would have tipped the scale against Stalin, making Axis victory possible, and delaying if not averting a showdown with the United States. Foreign minister Yosuke Matsuoka resigned from the Tokyo government when this option, which he favored, was rejected by his colleagues.

US naval cryptanalysts broke the Japanese diplomatic ciphers. The resulting intelligence, known as Magic, gave the Americans clear insight into Japanese intentions. Japan's decision to strike south was known within a few days in Washington, London, and Canberra. US President Franklin D. Roosevelt was well prepared when the Japanese moved into southern Indochina: the USA, in agreement with the British and the Dutch, froze Japanese assets and applied a further embargo that reduced trade with Japan by three-quarters. Roosevelt also ordered an embargo on high-octane gasoline and crude oil exports.

These embargoes had a devastating effect on the Japanese economy. In June 1941 a joint army-navy investigating committee concluded that Japan would run out of oil in mid-1944. Neither the Japanese government nor the Japanese people were willing to accept the massive loss of face that would have resulted from withdrawing from Indo-China and ultimately from China. There was no alternative but to seize the resources they needed from Malaya and the Dutch East Indies. The Japanese navy's planners also knew that the US would not remain neutral, and that with its forces in the Philippines the US would strike at the flanks of the Japanese invasion fleets.

The Japanese military believed the United States would not fight a major war with Japan because to do so would allow Nazism to succeed in Europe. Now was the time to make the strategy of 1936 work: hokushu nanshin or ‘hold north, go south’. As a first step, the Japanese occupied the rest of French Indochina in July 1941, which allowed them to create a new operating base at Cam Ranh Bay. The United States immediately retaliated by freezing Japanese funds and assets in the United States and putting a complete embargo on oil and strategic metals.

In the middle of 1941, the Japanese military drafted their optimistically titled ‘Operational Plan for ending the war with the US, Britain, the Netherlands and Chiang Kai-shek’. Initially, they intended to ‘await a good opportunity in the European war situation, notably collapse of mainland England, ending of the German-Soviet war and success of our policies towards India’. Emperor Hirohito said, after studying the plan: ‘I understand you are going to do Hong Kong after Malaya starts. Well, what about the foreign concessions in China?’ His Majesty was assured that such European properties would indeed be seized.

Tokyo was disappointed in its hopes of delaying a declaration of war until Germany’s victory in the west became complete. This miscalculation was almost as fundamental as the Japanese misreading of the enemy’s character. With the notable exceptions of a few such enlightened officers as Admiral Isoroku Yamamoto, naval commander-in-chief, the Japanese regarded the Americans as an unwarlike and degenerate people, whom a series of devastating blows would reconcile to a negotiated peace.

Japanese thinking was dominated by the new reality of the US oil embargo, an earnest of Roosevelt’s resolve. There is evidence that his subordinates translated a presidential desire to limit Japanese oil supplies and thus promote strategic restraint, rather than to impose an absolute embargo that accelerated the slide to war. Tokyo concluded that its only options were to bow to US demands, the least palatable of which was to quit China, or to strike swiftly.

Throughout the summer and early autumn of 1941, Japanese and American officials considered the immediate prospect of war, and neither set of diplomats and officers found much comfort in their calculations. American planners had worked on a variety of contingency plans since the fall of France, and Roosevelt had pushed them to accept the principle of Germany First if the United States was forced to declare war on the Axis nations at the same time. This meant that only token forces would be committed to the defense of Southeast Asia.

The defense of the Philippines and Allied colonies would have to be a holding action, conducted by scratch forces contributed by the British, Dutch, Australians, and Americans; land-based aircraft, a combined Allied fleet without carriers, and the colonial armies, stiffened with a few Europeans and American divisions, would have to do the best they could. The US Army provided only one regular division and an air force of 250 planes to the defense of the Philippines; all the other divisions were made of raw Filipino volunteers and draftees.

The war plan that appeared most likely to be used in autumn 1941 was Rainbow Five, which assumed little hope of stopping the Japanese. In the broadest terms, the only serious threat the United States could mount was a sortie into the Central Pacific by the Pacific Fleet, already weakened by redeployments to the Atlantic and the shuttling of reinforcements to bastions such as Guam, Wake Island, Midway Island, and the Philippines via Australia.

Historian David Kennedy has suggested that, since Germany was always the principal enemy of the Western democracies, Roosevelt would have better served his nation’s interests by averting war with Japan in order to concentrate upon the destruction of Nazism: ‘a little appeasement – another name for diplomacy – might have yielded rich rewards’. Kennedy argues that once Hitler was beaten, the ambitions of Japan could have been frustrated with vastly less expenditure of life and treasure, by the threat or application of irresistible Allied power. But this argument raises a large question: whether Roosevelt could ever have persuaded his people to fight the Germans, in the absence of overwhelming aggression such as Hitler refused to initiate.

The Japanese Cabinet met with Emperor Hirohito and decided to continue negotiations, while preparing to go to war if the negotiations were not successful by 10 October. When the deadline passed without progress in the negotiations, the War Minister, General Hideki Tojo, indicated that he had lost confidence in Prime Minister Konoye, who then resigned. Tojo became Prime Minister, while retaining his post as War Minister. He was determined to establish Japanese primacy in the Far East, to defeat the Western nations that had colonies in the Far East, to incorporate China into Japan, and to establish the East Asia Co-prosperity Sphere in the countries of south-east Asia.

Tojo appeared before the Emperor and argued that Japan had to seize the moment. Three days later the Japanese government issued war orders. Meanwhile, Japan offered not to seize any of the oil-producing islands if the US agreed not to interfere in China. Aware that Japan had already set a course for war, the US Secretary of State, Cordell Hull, restated the USA's conditions - that Japan withdraw from both Indochina and China, accept the legitimacy of Chiang Kai-shek's government, and, in effect, withdraw from the Tripartite Pact with Germany and Italy.

Japan’s foremost objective in South-East Asia was the oil of the East Indies, to which the Dutch exile government in London continued to refuse access. For a time, Japan’s generals cherished hopes of confining an assault to the European colonies, sparing America’s Philippines dependency. But Japanese naval commanders convinced their army counterparts that US belligerence was inevitable in the event of any ‘strike south’. Tokyo’s planners thereupon set about devising plans for a series of swift thrusts that would overrun the weak defences of Malaya, Burma, the Philippines and the Dutch East Indies.

Already Japanese forces were on the move. The ships that were to attack Pearl Harbor left their ports and began gathering at an anchorage in the remote northern Kurile Islands. Yamamoto sent Vice-Admiral Chūichi Nagumo, commander of the carrier strike force, a coded message: 'Climb Mount Niitaka'. It was the order to set sail for war.

A few days before the war started Tojo said: ‘Our empire stands at the threshold of glory or oblivion.’ Thus starkly did Japan’s militarists view their choices, founded in a grandiose vision of their rightful dominance of Asia. Yet even Tojo recognised the impossibility of achieving outright victory over the US. He and his colleagues instead sought to empower themselves by battlefield triumphs to achieve a negotiated settlement.

Although the Japanese intended to strike without warning, they still played out the diplomatic charade of presenting the US with an ultimatum to rectify a list of grievances. This diplomatic note was to be presented at 1.00 pm on the day of the attack at Pearl Harbor. As soon as the message was transmitted from Tokyo to Japan's Washington Embassy, it was deciphered by the Americans and it was passed to Roosevelt, who remarked, 'This means war.' The Japanese Embassy failed to decipher and translate the cable as quickly as the Americans, and the Japanese diplomats were not able to present the note formally to Cordell Hull until 2.30 pm. By then both Roosevelt and Hull knew that Hawaii had been under air attack for more than an hour.

The Allies had no knowledge of the Japanese carrier force's progress towards Pearl Harbor, but the Japanese could not keep their other war preparations secret. Roosevelt was given intelligence that a large Japanese convoy carrying 50,000 troops was at sea south of Formosa. Admiral Harold Stark, chief of US naval operations, sent a 'war warning' to Admirals Husband Kimmel and Thomas Hart of the Pacific and Asiatic fleets at Pearl Harbor and Manila. The message said that negotiations with Japan had ceased and that an 'aggressive move' by Japan was 'expected within the next few days'. Indications were that the Japanese might launch amphibious attacks against the Philippines, Thailand, Malaya, or possibly Borneo.

By 1941 the Japanese army consisted of 31 divisions, with a further 13 in the Kwantung Army. Each division generally numbered about 18,000 men. By Western standards, much of the army's heavy equipment was obsolete, but the troops were well trained and experienced from years of operations in China. The lack of adequate tanks and heavy artillery was not an important factor in jungle and island warfare. The Japanese air force was based mainly in China, but units were later deployed to larger islands such as New Guinea and the Philippines.

One of the strengths of the Japanese armed forces was the Bushido code of honor - the way of the warrior. All members of the armed forces were directly responsible to the Emperor. Military instructions emphasized absolute obedience to orders and forbade retreat in any circumstances. These attitudes led to fanatical resistance, often resulting in suicidal banzai charges, with the troops shouting the battle cry, 'Long live the Emperor!' Later in the war, Japanese aircraft pilots conducted suicidal kamikaze attacks on Allied ships. Another outcome was the atrocious treatment of Allied prisoners of war. But life was also hard and discipline brutal for the conscripted Japanese soldiers.

In December 1941 Japan's navy numbered 391 warships, including 10 battleships and 10 aircraft carriers. It was a well-trained force; its gunnery was good and its navigators were skillful. Some ships were new, with modern weapons - the Long Lance torpedo was exceptional - but others were older. Its strength was the naval air force, with its 1,750 fighters, torpedo bombers and bombers, operating from both aircraft carriers and island bases.

Japan's considerable industrial capacity allowed it to construct almost 70,000 aircraft between 1941 and 1945. However, Japan was not able to sustain the constant technological improvements that marked the Allied industrial effort. As the war progressed, the Allies had increasingly superior aircraft.

Theoretically, Japanese military operations were directed by Imperial General Headquarters, formed in 1937. In practice, the army and navy headquarters staff operated independently. Army operations were generally controlled by the China Expeditionary, Southern Expeditionary or Kwantung armies. Below this level were the area armies; these normally included several armies (equivalent to Western corps) and an air army. Most Japanese warships came under the Combined Fleet, headed in 1941 by Admiral Isoroku Yamamoto. This was subdivided into fleets with various compositions, such as the battleship force and the striking force.

Japan's military operations often suffered from a lack of clear strategic direction, caused by lack of cooperation between army and navy leaders. More generally, however, the Allies' main advantage lay in the industrial power of the USA.

Admiral Yamamoto had served in the US for several years and knew the power of the American industrial base. He was opposed to war, but became convinced that Japan's only hope was to destroy the US Pacific Fleet with a daring pre-emptive strike at its base at Pearl Harbor, Hawaii. The plan was approved and the Japanese navy began secretly training its pilots to undertake low-level torpedo attacks against ships in a remote bay similar to that at Pearl Harbor. Yamamoto finally selected the date for the attack - the morning of Sunday 7 December - when most of the US fleet, including its aircraft carriers, were usually in port for the weekend.

The calculations of Japan’s militarists were rooted in conceit, fatalism – a belief in shikata ga nai, ‘it cannot be helped’ – and ignorance of the world outside Asia. Japan’s soldiers had remarkable powers of physical endurance, matched by willingness for sacrifice. The country’s industrial and scientific base was much too weak to support a sustained conflict against the US.

At the outbreak of war, the American population was about twice that of Japan, but its industrial capacity was considerably greater. This industrial strength and large population enabled the USA to expand its armed forces at an unprecedented rate and to manufacture huge quantities of equipment and war materiel not only for its own forces but also for Allied forces. The US fought a war in Europe, but still deployed massive forces in the Pacific. General George C. Marshall remained the Chief of Staff of the US army throughout the war. Of the USAAF's 16 air forces, seven served in the Pacific and the China-Burma-India theaters. The US navy deployed the majority of its strength in the Pacific. Like the other services, it too underwent a huge expansion.

In early 1940 the US army numbered only 160,000, but after conscription was introduced in September 1940, it grew rapidly: in December its strength was 1.6 million; by March 1945 it had reached 8.1 million. These figures included the US Army Air Force (USAAF), which grew from 270,000 to 1.8 million in the same period.

In December 1941 the Pacific Fleet, based at Pearl Harbor, included nine battleships, three carriers, 21 heavy and light cruisers, 67 destroyers, and 27 submarines. The Asiatic Fleet, based at Manila, had three cruisers, 13 destroyers, 29 submarines, two seaplane tenders, and 16 gunboats. The total force was inferior to the Japanese navy, and this disparity was increased by the loss of battleships at Pearl Harbor. However, the USA's immense shipbuilding program soon changed the balance. During the war the US constructed 88,000 landing craft, 215 submarines, 147 carriers, and 952 other warships.

The USA's strength was its capacity to construct aircraft - almost 300,000 during the war - and its ability to improve aircraft designs each year. Although the USAAF was theoretically part of the army, it acted as an independent service. Its chief, General Hap Arnold, was one of the four members of the US Joint Chiefs of Staff.

The US navy included a strong air force (it grew from 11,000 in 1940 to 430,000 in 1945) and the US Marine Corps, which deployed six divisions, all in the Pacific. Admiral Ernest King was appointed Commander-in-Chief of the US fleet in March 1942 and remained in command throughout the war.

By December 1941 Britain had been at war with Germany and Italy for more than two years. Few military resources could be spared for the Far East. The imperial troops in Malaya included two Indian divisions and an understrength Australian division. Most of the aircraft there were inferior to those of the Japanese. There were few major naval units and no aircraft carriers. British forces in south-east Asia were always afforded a low priority for men and equipment. Operations would have been impossible without the assistance of forces raised in India. Britain provided a larger proportion of the air forces. The British Eastern Fleet operated in the Indian Ocean but was not a strong force until 1944.

By December 1943, for example, Air Command South-East Asia had an effective strength of 67 squadrons. Of these, 44 were from the Royal Air Force, 19 from the USAAF, two from the Royal Indian Air Force, one from the Royal Canadian Air Force, and one from the Royal Netherlands Air Force.

By 1945 the British Pacific Fleet was formed to operate with the Americans in the Pacific. With two battleships, four carriers, five cruisers, and 14 destroyers it was the largest and most powerful British fleet of the war.

Before the war, Australia had a minuscule regular army with about 80,000 part-time volunteers in the militia. The air force was also very small with about 160 mostly obsolete aircraft. Only the navy was even close to being ready for battle. The army and air force expanded through voluntary enlistment and, with navy units, they operated with British forces in the Middle East and Europe. After the outbreak of war in the Pacific, most of these units returned to Australia, where they became part of the South-West Pacific Area under General MacArthur.

New Zealand made a much smaller contribution than Australia, preferring to leave its largest expeditionary division in Europe. A small New Zealand division, along with air and naval units, fought in the Solomon Islands.

The Chinese armed forces were divided between those under the control of the Nationalist government, those organized by the Communist Party, and those under various warlords. Both the Nationalist and Communist forces expanded during the war. The Chinese air force was organized and flown by American volunteers.

The Nationalist army expanded from a force of about 1.2 million in 1937 to one of 5.7 million in August 1945, organized into 300 divisions. It was composed of conscripts, who were usually treated badly. Poorly equipped and inadequately trained, the Chinese divisions generally had a low level of capability. Several Chinese divisions fought under American command in Burma, where they performed creditably.

The main Communist army expanded from about 92,000 in 1937 to 910,000 in 1945. It concentrated on guerrilla warfare and on establishing good relations with peasant communities.

The days of peace for the United States dwindled to a precious few; but for Japan, Pearl Harbor brought a chance to end four years of war in China and free Japan from racial humiliation and economic interdependence. Blinded by their own sense of cultural superiority and distorted notions of industrial progress and economic determinism, the Japanese could not fathom why the United States should care about the Chinese, who exhibited an irrational traditionalism and pathetic social disorganization.

Having convinced themselves that the United States had no real gods but profit and consumption, the Japanese could not imagine that the flames which consumed the US Pacific Fleet’s battleships on 7 December 1941 would ignite a deadly firestorm of revenge, racism, embarrassment, and idealism in the heart of the American people.

Though Winston Churchill strained every sinew to induce the US president to lead his nation into belligerence before Pearl Harbor, it was fortunate that his efforts failed. In the unlikely event that Roosevelt could have forced a declaration of war on Germany through the US Congress, from that point on he would have led a divided nation. Until December 1941, public opinion remained stubbornly opposed to fighting Hitler. A much higher proportion of people favored stern action against the Japanese.

Even after war was declared in December 1941, and indeed until the end of hostilities, few Americans felt anything like the animosity towards Germans that they displayed against the Japanese. This was not merely a matter of racial sentiment. There was also passionate sympathy for the horrors China had experienced, and continued to experience, at Japanese hands. Most Americans deplored what the Nazis were doing to the world, but would have remained unenthusiastic or indeed implacably hostile about sending armies to Europe, had not Hitler forced the issue.