What Was Operation Ichi-Go?

Operation Ichi-Go (or ‘Operation Number One’) was Japan’s largest offensive against the Chinese army during World War II.

Mar 2, 2024By Matt Whittaker, BA History & Asian Studies


1944 became the year that Imperial Japan’s fortunes turned sour. Thus, Operation Ichi-Go came into being. Launched in China in April 1944, Operation Ichi-Go was Imperial Japan’s biggest offensive in World War II. Since 1943, the American steamroller began the grind closer to Japan’s Home Islands.


The Sino-Japanese War

Japanese troops enter Manchuria. Source: Wikimedia
Japanese troops enter Manchuria. Source: Wikimedia


Japan’s difficult war with Nationalist China predated World War II, starting with the 1937 Marco Polo Bridge Incident. This sparked a Japanese invasion, and soon, major port cities and swaths of northern China fell quickly. Other than flare-ups, this situation changed little until 1944.


A Battle with Imperial Japan

Japanese World War II military conquests. Source: David Rumsey
Japanese World War II military conquests. Source: David Rumsey


Imperial Japan’s mind-boggling victories early in the war made the Empire look unbeatable. However, the tide changed drastically with the Battles of Midway, Guadalcanal, and New Guinea. Even the fortress city of Singapore fell. The successful and rapid American island-hopping campaign came ever closer with each victory, making the Home Islands vulnerable to strategic bomber attacks. In China, Japan learned that B-29 bases had started construction or were done by late 1943. The huge B29’s range and size allowed for raids against Japan. In response, Japan planned a vigorous offensive. 


Operation Ichi-Go

Operation Ichigo Source: WW2DB
Operation Ichi-go Source: WW2DB


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This offensive needed to accomplish different goals. First, the airfields in central China must be destroyed. Secondly, connecting the north-to-south rail lines would enable uninterrupted communications between Korea and occupied French Indochina. The unrelenting Allied submarine attacks by 1944 had decimated Japan’s shipping – this rail would bypass that danger. Finally, wiping out engaged Nationalist Chinese armies in southern and central China.


To prepare, Japan assembled an army of 400,000, including divisions transferred from Manchukuo and Korea. And in a rare move for the Imperial Army, the Ichi-Go armies received 800 tanks and 15,000 motor vehicles. Given Japan’s tough strategic situation, such provisioning shorted other armies of needed equipment.


The Allied Reaction

Japanese soldiers advance. Source: Wikimedia Commons
Japanese soldiers advance. Source: Wikimedia Commons


The Imperial Army’s actions did not go unnoticed. Due to demands for men, ammunition, and materials from other theaters, few battles happened in China. Now, several sources warned the Chinese Nationalist government and the Americans. Both sides did little, clashing over different military priorities and political goals. The Americans blamed the Nationalists, under Chiang Kia-shek, for not doing enough. They accused Kia-shek of holding nearly 500,00 soldiers to fight the Communists later. This let the Japanese, before Ichi-Go, transfer divisions to fight in the Pacific. Kai-shek also ignored the corruption among his generals, pilfering American supplies.


All Falls Apart

Boeing B-29 Source: NASA
Boeing B-29 Source: NASA


Operation Ichi-Go launched on April 19, 1944, in central China’s Henan Province. By the end of May, the industrial hub of Luoyang fell with most of the province. The Japanese following took on Hunan Province, clearing Nationalist forces, but at Hengyang’s B-29 airbase, the Nationalists fought hard. Both were captured but with heavy Japanese losses.


The National Army fighting the Japanese varied in quality. Some, trained by the Americans, fought hard, but most were raw recruits. The Nationalist Army often did broad rural sweeps to find manpower. Most Nationalist armies hardly fought, melting away as the Japanese invaded. Hostility sometimes got bad enough as peasants fought back, killing the officers and capturing the soldiers. 


The initiative stayed with Japan into September. When the Imperial Army invaded Guangxi Province, some 150,000-plus Nationalist troops again retreated. Then the three B-29 bases fell. Japanese use of poison gas and tanks helped their advance. Not all Chinese retreated. At Henyang, the Chinese troops dug in, evacuating 300,000 civilians in three days. The city’s airfield had housed B-29s until days before the attack, and two rivers joined here, making the city an important communications hub. The Imperial Army attack started on June 23, 1944, quickly surrounding the city.


The Japanese expected an easy victory, using their proven tactic of air bombing, mass artillery, poison gas, and firebombs. For forty-seven days, the 18,000 Chinese held out despite little ammunition and a lack of replacements. The Imperial Army attacked three times, finally taking it on August 8, 1944. The Imperial Army suffered 19,000 killed out of 60,000 casualties. 


A Command Crisis

Nationalist leader Chiang Kai-shek. Source: United States Navy
Nationalist leader Chiang Kai-shek. Source: United States Navy


Operation Ichi-Go cleared out the Nationalist Chinese from nearly three provinces and wreaked political chaos. Tensions between Nationalist leader Chiang Kai-shek, President Roosevelt, and General Stillwell (American theater commander) blew up. Stillwell, backed by Roosevelt, demanded control of all Chinese forces. Kai-shek balked, seeing Stillwell as interfering. He was replaced, but China’s influence diminished.


Ichi-Go’s Impact

Japanese plane Carolina Islands Source: U.S. Navy.
Japanese plane Carolina Islands Source: U.S. Navy.


Japan’s last great World War II offensive came as a last gasp. Irreplaceable equipment and trained men needed elsewhere were lost. Operation Ichi-Go captured airfields and connected Korea and Vietnam. However, the Americans just shifted the B-29s to the closer and newly conquered Marianas, much closer to the Home Islands, allowing the bomber offensive to continue.

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By Matt WhittakerBA History & Asian StudiesMatt Whittaker is an avid history reader, fascinated by the why, how and when. With a B.A. in History and Asian Studies from University of Massachusetts, he does deep dives into medieval, Asian and military history. Matt’s other passion besides family is the long-distance Zen-like runs.