After the Japanese occupied Xuzhou in May 1938 , they sought to actively expand the scale of the invasion . The IJA decided to send a vanguard to first occupy Anqing for use as a forward base for an attack on Wuhan , then for its main force to attack the area north of the Dabie Mountains moving along the Huai River , eventually occupying Wuhan by way of the Wusheng Pass . After that , another detachment would move west along the Yangtze . However , due to the Yellow River flood , the IJA was forced to abandon the plan of attacking along the Huai , and decided to attack along both banks of the Yangtze instead . On 4 May , the commander of the IJA forces , Shunroku Hata , organised approximately 350,000 men of the Second and Eleventh Armies for the fighting in and around Wuhan . Under him , Yasuji Okamura commanded five and a half divisions of the Eleventh Army along both banks of the Yangtze in the main assault on Wuhan while Prince Naruhiko Higashikuni commanded four and a half divisions of the Second Army along the northern foot of the Dabie Mountains to assist the assault . These forces were augmented by 120 ships of the Third Fleet of the Imperial Japanese Navy under Koshirō Oikawa , more than 500 planes of the Imperial Japanese Army Air Service as well as five divisions of Japanese forces from the Central China Area Army to guard the areas in and around Shanghai , Beijing , Hangzhou , and other important cities , thus protecting the back of the Japanese forces and completing the preparation for the battle
Yellow River flood
1938 Yellow River flood
Battle of Wuhan