After the
Mukden Incident on 18 September 1931, the 39th brigade of
20th Division was detached, reinforced by the 29th Infantry Regiment and stationed in the
Liaodong Peninsula at
Jinzhou. In December 1931, the rest of division has loso moved to
Jinzhou. The whole
20th division was withdrawn in April 1932. However, following the
Marco Polo Bridge Incident from 11 July 1937, the division was again dispatched to the north China theater of operations under the command of Lieutenant General
Bunzaburō Kawagishi, as part of the
1st army. The division participated in the
Beiping–Hankou Railway Operation and
Battle of Taiyuan, but returned to its base at
Keijo without having seen significant combat and remained as a reserve and garrison force in Korea throughout the remainder of
Second Sino-Japanese War, mainly intended to counter an expected Soviet
deep operation advances. From the start of the war until its return to Japan in January 1940, the 20th Division suffered 4,742 killed, 686 dead from illnesses, and 13,307 wounded. On 1 July 1940, the
reconnaissance regiment replaced the cavalry regiment, which was detached in 1942. Also, on 16 July 1941, the 77th infantry regiment was detached and transferred to the newly created
30th division, thus converting the
20th division to the
triangular division format. In 1942, the division was sent to southern
Manchukuo, and its field artillery regiment was changed to a mountain artillery regiment. During the fighting in New Guinea, the division consisted of three infantry regiments—
78th,
79th and
80th—along with the 26th Field Artillery Regiment. the 20th Reconnaissance Regiment, the 20th Engineer Regiment and the 20th Transport Regiment. From October 1943, the 20th Infantry Division under Lieutenant General
Shigemasa Aoki, was transferred to the
Japanese Eighteenth Army in the Southern Area Command (
New Guinea). Aoki died of
malaria in July 1943, and was replaced by Lieutenant General
Shigeru Katagiri, who established his headquarters near Gali, and marched with his troops to reinforce
Finschhafen after the Allied
landings at Lae and
Nadzab on 4 September 1943. Katagiri was the primary Japanese commander at the
Battle of Finschhafen between September and October 1943 in the
Huon Peninsula campaign. He gathered his forces at
Sattelberg but was forced to retreat after being defeated during the
Battle of Sattelberg on 25 October 1943. During the
Battle of Hollandia at the end of April 1944, Shigeru Katagiri was killed in combat while en route from
Madang to
Wewak. He was replaced by Major General
Masutaro Nakai, who was promoted to lieutenant general in April 1945. The surviving forces of the Nakai Detachment of the
20th division held out against the Australian Army in the
Markham, Ramu and Finisterre campaigns and other combat operations in New Guinea until the end of the war. Of the approximately 25,000 men in the 20th Division, only 1,711 survived the war. More men died in New Guinea from
malaria and
malnutrition than from combat with the Americans or Australians. ==See also==