The Marco Polo Bridge Incident: Where Japan’s Full-Scale Invasion of China Began

July 7, 1937. Late night. The stone lions of the Marco Polo Bridge stood silent in the moonlight, as they had for centuries.

That night, a unit of the Japanese China Garrison Army was conducting what it called a “military exercise” near the bridge. Then, using the pretense of a “missing soldier,” Japanese officers demanded entry into Wanping town to conduct a search. When the Chinese garrison—Unit 219 of the 37th Division, 29th Army—refused, Japanese troops opened fire.

The Chinese defenders returned fire.

The Marco Polo Bridge Incident had begun.

I. This Was Not an Accident—It Was Deliberate

A persistent narrative frames the July 7th Incident as some kind of “accidental clash,” as if the war between China and Japan emerged from a lost soldier and a misfire. This framing inverts the truth entirely.

Japan’s aggression against China was systematic planning, not a reaction.

Since the Mukden Incident of 1931, Japan had occupied all of Manchuria. In 1932, the January 28th Incident brought Japanese assault on Shanghai. In 1933, Japanese forces breached the Great Wall line, directly threatening Beiping and Tianjin. In 1935, the North China Crisis forced the Chinese government into the He-Yume Agreement, effectively placing Hebei and Chahar provinces under Japan’s sway.

By 1937, Japan had stationed elite garrison troops in North China, with over 8,000 troops surrounding the Beiping-Tianjin area. Fengtai was their forward position, and from there they conducted “exercises” with Wanping town and the Marco Polo Bridge as their explicit targets—over and over again.

This was not military training. It was systematic intimidation and preparation for war.

Before July 7th, Japan had repeatedly manufactured provocations: in the 1936 Fengtai Incident, Japanese troops had already wounded Chinese soldiers with bayonets. Each time, Japanese demands grew bolder. Each time, the space for Chinese forbearance shrunk.

So when Japanese troops manufactured another incident on the night of July 7, 1937, it was not chance—it was the inevitable outcome of Japan’s policy of nibbling away at Chinese territory. Without July 7th, there would have been August 7th, or September 7th.

II. The 29th Army: The Defenders Who Are Often Forgotten

The primary Chinese defenders at the Marco Polo Bridge were members of the National Revolutionary Army’s 29th Army. Their commander was Song Zheyuan. The unit traced its roots to Feng Yuxiang’s Northwestern Army—a force forged in China’s harsh interior and hardened by decades of conflict.

The Northwestern Army’s tradition valued one thing above all: fearlessness in battle. The 29th Army had already demonstrated its anti-Japanese resolve during the Great Wall battles of 1933, where the Hejibin brigade inflicted serious casualties on Japanese forces at Dachang.

On the night of the incident, Battalion Commander Ji Xingwen ordered: “Hold positions at all costs. Fight back to the end.” It was the right call. The Marco Polo Bridge was the last strategic position guarding Beiping—once lost, the city would be surrounded from three sides.

But the July 8th telegram from the central government was decisive: “Wanping must be defended. Do not retreat. Full mobilization is authorized in preparation for expansion of the situation.”

On the same day, Chiang Kai-shek issued his statement from Lushan: “We have reached the last moment. Every person, regardless of region or age, bears responsibility for defending the land.”

This was the fundamental turning point in the Nationalist government’s policy toward Japan.

III. From Local Confrontation to Total War

The Marco Polo Bridge Incident itself was, militarily, a limited affair. What transformed it was Japan’s deliberate choice to “escalate.”

On July 11th, Japan’s cabinet convened an emergency session and issued a “Declaration on Dispatch of Troops,” deciding to reinforce North China. The Kwantung Army’s 1st and 11th Independent Mixed Brigades began moving through the Great Wall. On July 28th, Japanese forces launched a general offensive on Nanyuan; Deputy Army Commander Tong Linge and 132nd Division Commander Zhao Dengru were killed in action. On July 30th, Beiping and Tianjin fell.

From there, Japanese forces pushed west and south along the Beijing-Hankou and Tianjin-Pukou railways. On August 13th, the Battle of Shanghai erupted—a battle Japan expected to conclude in three months but which dragged on for three brutal months, ultimately turning into a grinding war of attrition.

By September 1937, the Second United Front between the Nationalists and Communists was formally established. The Red Army was reorganized as the 8th Route Army; the southern guerrilla forces became the New 4th Army. China had formed an Anti-Japanese National United Front.

After the Marco Polo Bridge Incident, there was no more peace between China and Japan—only war.

IV. The Historical Crucible

The Marco Polo Bridge Incident marked not only the beginning of Japan’s full-scale invasion of China, but also the turning point of the Chinese nation’s awakening.

In modern Chinese history, no foreign invasion as thorough as 1937 shattered illusions so completely—the illusion that Japan could be negotiated with, that Western powers would uphold justice, that “limited resistance” was viable.

The gunfire at the Marco Polo Bridge forced China, for the first time, into genuine national resistance.

Mao Zedong later wrote in On Protracted War: “Weapons are an important factor in war, but not the decisive factor; the decisive factor is people, not material.” The practical foundation of that statement was the resistance will displayed by the Chinese military and civilians after July 7th.

Epilogue

The stone lions of the Marco Polo Bridge survived the war and still stand there today.

89 years ago, that moonlight shone on a city about to fall. Today, it shines on a modern, thriving metropolis.

History must not be forgotten—not for the sake of grievance, but for the sake of remembering: what price does a nation pay to rise from the edge of destruction?

This article is part of the ongoing educational series on Japanese militarism. For primary source materials on the Marco Polo Bridge Incident, consult the collections of the Second Historical Archives of China and the Memorial Hall of the War of Resistance Against Japanese Aggression.