Operation Ko

'Ko' was a Japanese offensive in central China, launched as the first of the three components of the 'Ichi' strategic offensive, whose other components were the two parts of 'To' (iv) fought farther to south (17 April/June 1945).

The operation was planned in Peking and Nanking by General Yasuji Okamura’s China Expeditionary Army with the object of eliminating the Chinese salient to the north of the Yangtse river, and thereby clearing the strategically vital rail line linking Chengchow and Hankow. The shoulders of this salient were at Tungkwan in the north and near Laohokow in the south, and its apex jutted into the Japanese-held portion of China as far east as Kaifeng in the sector held by Lieutenant General Takari Takamori’s 12th Army and Lieutenant General Senichi Kushibuchi’s 34th Army of General Naosaburo Okabe’s 6th Area Army.

This Chinese salient was an important Japanese target for the three reasons that it contained a valuable rice harvest, sheltered the two major bases of Major General Claire L. Chennault’s US 14th AAF at Ankang and Laohokow, and included the strategic rail nexus of Chenghsien. The rice harvest was important to the Japanese as it would bolster their capabilities while reducing those of the Chinese from whom it could hopefully be captured immediately after the harvest, the reduction of the air bases would lessen the threat to significant Japanese targets in China and Manchukuo (the Japanese puppet state in Manchuria), and the capture of Chenghsien would allow a useful reduction in Japanese local force strengths by allowing greater strategic mobility and speed as lines radiated from this key city to Peking in the north, to Tungkwan and Sian in the west, to Hankow, Wuchang, Changsha and Canton in the south, and to Suchow and Haichow in the east.

Otherwise known as the Battle of Central Henan, 'Ko' was the first part of 'Ichi', and involved substantial Japanese forces under the local command of Lieutenant General Eitaro Uchiyama’s 15th Area Army against a smaller Chinese strength under the local command of Lieutenant General Tang En-po, the deputy commander of General Chiang Ting-wen’s 1st War Area, for the defence of the strategic position of Luoyang.

In 'Ko' the Japanese committed some 390,000 men of Lieutenant General Yuichiro Nagano’s 37th Division of Lieutenant General Teiichi Yoshimoto’s 1st Army and Lieutenant General Jinkuro Ochiai’s 27th Division, Lieutenant General Takeo Fujioka’s 62nd Division, Lieutenant General Yoshitaro Hayashi’s 110th Division, Lieutenant General Hideo Yamaji’s 3rd Armoured Division, the 7th Independent Mixed Brigade, the 9th Independent Mixed Brigade and the 4th Cavalry Brigade of the 12th Army as well as some 230 aircraft of the 5th Air Army.

The Chinese-held area threatened by 'Ko' was the responsibility of Chiang’s 1st War Area, though Tang, Chiang’s deputy, exercised operational command of most of the Chinese ground forces involved in 'Ko', which totalled about 100,000 men 1.

'Ko' began on 17 April as an advance across the Huang river into Henan with the object of clearing the railway between Chengchow and Hankow. The attacking force was spearheaded by three infantry divisions and the 3rd Armoured Division of Uchiyama’s 12th Army, and was supported by several independent mixed brigades. The Japanese spearheads crossed the Huang river around Zhengzhou late in April and defeated the Chinese forces near Xuchang, then wheeled to the west to besiege Luoyang, which was defended by three Chinese divisions. The 3rd Armoured Division began to attack Luoyang on May 13 and took it on May 25, and the railway had been secured by June. The 30 Chinese defending divisions enjoyed no support from the people of Henan, who were embittered by continuing taxation during a period of famine, and were allegedly alienated still further from the nationalist cause by communist collaborators.

Thus 'Ko' was more than an adjunct to 'Ichi', having decidedly important strategic ramifications of its own, and great efforts were made by the Japanese to secure success. The operation came as a complete surprise to the Chinese, who were forced back throughout the salient, especially in the south where the air base of Laohokow fell, much to the chagrin of Chennault. However, the Chinese had started to check the Japanese thrust by a time in the middle of June 1945 as a result of the rejuvenating efforts of Lieutenant General Albert C. Wedemeyer, who had succeeded Lieutenant General Joseph W. Stilwell as chief-of-staff to Generalissimo Chiang Kai-shek during the earlier stages of 'Ichi' and was also exercising operational command of the Chinese forces in the field.

At about this time Okamura decided that the offensive warranted no further expenditure of Japanese effort and resources, for the rice harvest had been captured, Chenghsien taken, and one of the two US air bases in the area seized. Moreover, the threat along the Siberian/Manchukuoan border was looking increasingly dangerous as Soviet troops were moved into the theatre at the time of terminal hostilities in Europe, so Okamura decided to use the strategic mobility provided by possession of Chenghsien to reduce his forces in China to bolster those in Manchukuo.

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These forces were Lieutenant General Sun Wei-ju’s 4th Army Group (Lieutenant General Chang Yao-ming’s 38th Army with part of the 17th Division and the New 35th Division, and Lieutenant General Li Hsing-chung’s 96th Army with part of the 17th Division and the New 14th Division), Lieutenant General Liu Mao-en’s 14th Army Group (Lieutenant General Wu Ting-lin’s 15th Army with the 64th and 65th Divisions), Lieutenant General Liu Kan’s Army (Lieutenant General Hsieh’s 4th Provisional Army with the 47th Division and 4th Provisional Division, and Lieutenant General Han Hsi-hou’s 9th Army with the 54th Division and New 24 Division), Lieutenant General Ho Chu-kuo’s 15th Army Group (Lieutenant General Liao Tze-kun’s 2nd Cavalry Army with the 3rd Cavalry Division and 14th Provisional Division, the 8th Cavalry Division, and the 1st, 2nd and 3rd Provisional Brigades), Lieutenant General Chen Ta-ch’ing’s 's 19th Army Group (Lieutenant General Huo’s 9th Provisional Army with the 111th and 112th Divisions and the 30th Provisional Division), Lieutenant General Li Hsien-chou’s 28th Army Group (Major General Wu Shao-chou’s 85th Army with the 11th Reserve Division, 23rd Division and 110th Division, Lieutenant General Ku Hsi-chou’s 89th Army with the 20th Division and New 1st Division, and Lieutenant General Liu Chang-yi’s 15th Provisional Army with the 27th and 29th Provisional Divisions), General Wang Chung-lien’s 31st Army Group (Major General Huo Shou-yi’s 12th Army with the 22nd and 29th Divisions and the 55th Provisional Division, Lieutenant General Shih Chueh’s 31st Army with the 4th, 81st, 89th and 117th Divisions and the 16th Provisional Division, Lieutenant General Ma Li-wu’s 29th Army with the 91st and 193rd Divisions and 16th Provisional Division, and the New 42nd, 43rd and 44th Divisions), and Lieutenant General Li Chia-yu’s 36th Army Group (Lieutenant General Li Tsung-fan’s 47th Army), Lieutenant General Kao Shu-hsun’s 39th Army Group (Major General Hu Po-han’s New 8th Army with the New 6th Division and 29th Provisional Division, the 14th Army with the 83rd, 85th and 94th Divisions, and Major General Lai Ju-hsiang’s 78th Army with the New 42nd, 43rd and 44th Divisions).

Elements of the 8th War Area which arrived as reinforcements under the deputy commander of the 8th War Area, General Hu Tsung-nan, were Lieutenant General Ma Fa-wu’s 40th Army with the 39th and 106th Divisions and the New 4th Division, Lieutenant General Chang Cho’s 1st Army with the 167th Division, Major General Li Cheng-hsien’s 16th Army with the 3rd Reserve Division and 109th Divisions, Lieutenant General Chou Shih-mien’s 27th Army with the 128th Division, and Lieutenant General Liu An-chi’s 57th Army with the 8th and 97th Divisions and the New 34th Division.