Imperial Japan's quest for power and the 1937 invasion of China
By the mid-1930s, Japan had already annexed Korea in 1910 and invaded Manchuria in 1931, and it had withdrawn from the League of Nations in 1933.
Its generals increasingly silenced elected politicians and expanded military capabilities in preparation for conquest, and they cast China as a fractured civilisation that they presented as ripe for invasion.
When Japanese soldiers clashed with Chinese troops at the Marco Polo Bridge in July 1937, they triggered a brutal war that Japan had long prepared for and that China could neither easily avoid nor win quickly.
The Meiji transformation and the roots of expansion
After 1868, Japan’s ruling elite had effectively removed the Tokugawa shogunate from power and had created a modern industrial state centred around a constitutional monarchy.
They adopted German legal systems, British naval models, and Western technologies, and they also constructed a national army through universal conscription, which the government formally introduced in 1873.
Railway networks expanded and banks emerged under government charters, and Tokyo positioned itself as the capital of a new and confident Japanese nation-state.
Major industrial companies such as Mitsubishi and Mitsui benefited from close ties to the state.
The state’s purpose shifted from defensive modernisation to territorial expansion.
Over time, political theorists and military officials argued that, in their view, Japan could not secure its industrial economy without controlling access to markets and natural resources across Asia.
They identified Korea and China as both vulnerable and essential. In 1894, Japan declared war on the Qing Empire and secured a clear victory.
Under the Treaty of Shimonoseki in 1895, China ceded Taiwan and paid 200 million taels of silver in reparations, and it granted commercial rights to Japanese companies.
The treaty also ceded the Liaodong Peninsula, but the later Triple Intervention by Russia and France, together with Germany, forced Japan to return it, which caused long-term resentment.
The war confirmed Japan’s belief in its superiority over other Asian powers and legitimised future expansion.
The growth of militarism and racial ideology
By the early twentieth century, military officials had steadily increasing influence over policy, both through institutional authority and control over culture.
Military academies emphasised emperor worship and racial theory, and they promoted samurai traditions, while political debate increasingly narrowed around loyalty and purity, and it praised sacrifice.
Textbooks and newspapers reinforced the idea that Japan had a special role in leading Asia, and films repeated the same message.
Generals claimed that, in their view, Japan alone could remove Western colonialism from the region and restore order.
After Japan defeated Russia in 1905, it formally annexed Korea in 1910 after controlling the peninsula for five years under the Eulsa Treaty.
It secured new colonies and commercial privileges during the First World War. In 1915, Japan presented China’s republican government with the Twenty-One Demands, which aimed to give Japan greater control over mines and railways, as well as over internal administration.
Group V of the demands proposed that Japanese advisors should hold key government positions, which triggered fierce Chinese resistance.
When the Treaty of Versailles awarded Japan the former German colony of Shandong, Chinese outrage deepened.
This betrayal, especially after China had supported the Allies during the war, directly influenced the May Fourth Movement in 1919.
Japan signed naval and disarmament treaties with Western powers, but army officers increasingly rejected international cooperation as weakness.
Soon after, a series of domestic problems, such as the assassination of Prime Minister Hara Takashi in 1921 and the financial panic of 1927, allowed military leaders to push harder for rearmament and expansion.
Assassination plots and coup attempts by young officers revealed the growing confidence of the army, especially those stationed in China and Manchuria, who often acted without authorisation from Tokyo.
China’s internal crisis
After the Qing dynasty collapsed in 1911, China struggled to establish a stable central government.
While Sun Yat-sen and the Kuomintang promoted republican nationalism, their movement struggled against regional warlords and Communist insurgencies.
Power stayed divided, and infrastructure crumbled as foreign powers maintained special privileges and military garrisons across treaty ports and railway zones.
During this period of weakness, Japan steadily deepened its involvement in Manchuria, where the South Manchuria Railway Company became both an economic and intelligence tool.
In 1931, officers in the Kwantung Army included Colonel Seishirō Itagaki and Lieutenant Colonel Kanji Ishiwara, and they staged the Mukden Incident when they placed explosives on a section of track and then blamed Chinese forces for the damage.
The staged attack provided the justification for a rapid invasion. Japanese troops seized control of Manchuria and declared the creation of a new puppet state, Manchukuo, with former Qing emperor Puyi, who was a symbolic figurehead.
Eventually, the League of Nations condemned the invasion, but no direct military action followed.
Japan left the League in 1933 and stepped up its activities in northern China.
Meanwhile, Chiang Kai-shek increasingly focused on internal unity. Although he had previously launched the Fifth Encirclement Campaign against the Chinese Communists in 1933–1934, by 1937 he had largely prioritised unifying nationalist forces to confront Japan.
Japanese officers took advantage of this situation and expanded garrisons, and they backed proxy forces to undermine the Kuomintang’s hold on northern provinces.
The Marco Polo Bridge Incident
On 7 July 1937, Japanese troops carried out night training exercises near the Marco Polo Bridge west of Beijing.
When one soldier failed to report back, Japanese commanders demanded entry to the nearby Chinese-controlled town of Wanping to conduct a search.
Chinese officers refused, and a brief exchange of gunfire followed. Some historians argue that the missing soldier had returned before the firing began and that the incident was manipulated to justify military escalation.
Although both governments initially sought to contain the incident, field commanders escalated the conflict by deploying additional troops, and this escalation quickly resulted in intense fighting around the capital.
As pressure mounted, Japanese high command authorised a full-scale invasion.
Within days, Japanese forces overran Beijing and Tianjin, then advanced southward to Shanghai.
The Battle of Shanghai unfolded between August and November, involving over a million troops.
Chinese forces under General Zhang Zhizhong and his elite German-trained 87th and 88th divisions mounted a determined defence.
Japanese forces used naval bombardment and aerial bombing, and they also deployed poison gas, while Chinese defenders, despite heavy losses, mounted stiff resistance.
Japanese generals, determined to destroy Chinese morale, launched further attacks toward Nanjing, which had been the Nationalist capital before being evacuated by Chiang Kai-shek in late November.
In December 1937, Japanese divisions entered Nanjing and carried out six weeks of massacres and rapes, together with large-scale destruction.
The Nanjing Massacre, also known as the Rape of Nanjing, resulted in the deaths of an estimated 200,000 to 300,000 civilians and surrendered soldiers who had been left defenceless.
Eyewitness accounts by foreign diplomats and by missionaries such as Minnie Vautrin and accounts by journalists such as John Rabe documented widespread atrocities, which became some of the most damning evidence of Japanese brutality in the twentieth century.
General Iwane Matsui was convicted by the Tokyo War Crimes Tribunal and sentenced to death for his role in the violence.
Prince Asaka, although implicated by some sources, was never tried due to his imperial status.