Battle of Kunlun Pass

The Imperial Japanese Army launched a major offensive into Guangxi province with the intention of eliminating the Chinese supply route through French-controlled Vietnam. The elite Japanese 5th Division was given the task of spearheading the Japanese offensive. After occupying Nanning in November 1939, the Japanese captured the key point of Kunlun Pass and were poised to attack the Chinese forces that protected Chongqing, the wartime capital.

Realizing that inaction would result in being cut off, General Bai Chongxi, himself a native of Guangxi, asked the Nationalist Government for reinforcements. Chiang Kai-shek in turn, dispatched the 5th Corps from Hunan province to fight the Japanese.

The 5th Corps was the most elite unit in the National Revolutionary Army, and it was also the only Chinese unit that had tanks and armored vehicles. Its soldiers were combat-hardened veterans from previous engagements against Japanese forces, and as a result, morale was high. General Du Yuming, commander of the 5th Corps, dispatched two divisions to attack the Japanese-held Kunlun Pass. The New 22nd Division's attack ended up cutting off Japanese reinforcements from the rear and also resulted in the death of the Japanese commander, Major General Masao Nakamura.^[12]

The Japanese reacted immediately by sending in the elite unit of the Japanese 5th Division, the 21st Brigade, which had also participated in the Russo-Japanese War, nicknamed the "unbreakable sword". Faced with the serious possibility of being completely cut off, the Japanese army ended up relying on air power for the delivery of vital supplies. Before Major General Nakamura's death, he admitted in his diary that the Chinese soldiers' fighting ability had surpassed the Russians whom the Brigade encountered in Manchuria. At a heavy cost, the Chinese army claimed to have inflicted a total of 10,000 casualties on the Japanese. Among the claimed Japanese casualties were 5,000 fatalities, including over 85% of all officers, such as Major General Nakamura, Colonel Sakata Gen'ichi (commander of the 42nd Regiment and acting commander of the 21st Brigade), Colonel Miki Kichinosuke (commander of the 21st Regiment), Colonel 生田滕一 (deputy commander of the 21st Regiment), 杵平作 (commander of the 1st Battalion), 官本得 (commander of the 2nd Battalion), 森本宮 (commander of the 3rd Battalion), among others.^{[9]: 101–102} Additionally, the Chinese claimed to have taken 102 Japanese troops as prisoners, and captured 79 horses, 10 mountain guns, 12 field guns, 10 anti-tank guns, 102 light machine guns, 80 heavy machine guns, and 2,000 rifles.^[9]: 102

The Japanese army reported Colonel Miki's 21st infantry regiment (including Matsumoto's battalion of the 42nd infantry regiment temporarily under Colonel Miki's command) as 376 killed, 755 wounded, and 37 missing. The losses of the 9th infantry brigade and the two regiments of the Taiwan Mixed Brigade are 112 killed and 481 wounded. The total amounts to 1,761 killed, wounded, or missing. The losses of the 42nd infantry regiment (excluding Matsumoto's battalion) and units directly under the 5th division are unknown.

Kaji Wataru, a Japanese member of the Chinese Resistance, and his Anti-War League, which was made up of Japanese POWs who had defected to the Chinese resistance, were sent to Kunlun during the battle to launch a psychological warfare campaign against Japanese troops in the region.^[13] Their operations were reported by an Australian Newspaper during the war.^[14]