By April 1945, China had already been at war with Japan for more than seven years. Both nations were exhausted by years of battles, bombings and blockades. After Japanese victories in Operation Ichi-Go, Japan were losing the battle in Burma and facing constant attacks from Chinese Nationalists forces and Communist guerrillas in the country side. The Japanese army began preparations for the Battle of West Hunan in March 1945. Japanese mobilized 34th, 47th, 64th, 68th and 116th Divisions, as well as the 86th Independent Brigade, for a total of 80,000 men to seize Chinese airfields and secure railroads in West Hunan by early April. In response, the Chinese National Military Council dispatched the 4th Front Army and the 10th and 27th Army Groups with He Yingqin as commander-in-chief. At the same time, it airlifted the entire Chinese New 6th Corps, an American-equipped corps and veterans of the Burma Expeditionary Force, from Kunming to Zhijiang. Chinese forces totaled 110,000 men in 20 divisions. They were supported by about 400 aircraft from Chinese and American air forces. Chinese forces achieved a decisive victory and launched a large counterattack in this campaign. Concurrently, the Chinese managed to repel a Japanese offensive in Henan and Hubei. Afterwards, Chinese forces retook Hunan and Hubei provinces in South China. Chinese launched a counter offensive to retake Guangxi which was the last major Japanese stronghold in South China. In August 1945, Chinese forces successfully retook Guangxi.[citation needed]

In 1945, how many years had Japan already been at war with China?