Short answers, pulled from the story.
The Japanese Eleventh Army launched the Third Battle of Changsha on the 24th of December 1941. Its goals were to sever Chinese communication lines to British Hong Kong and seize the region's rice supply. The attack also reflected General Anami's personal determination after Chinese claims of defeating him in an earlier Changsha offensive in late 1941.
General Xue Yue, nicknamed the "Tiger of Changsha," commanded the overall Chinese defense. The city was held by the 10th corps under Li Yutang. Li had been dismissed after the Second Battle of Changsha but was reinstated when his replacement had not yet arrived.
The Third Battle of Changsha ended with a Japanese retreat, with withdrawal orders issued on the 3rd of January 1942. Chinese forces had encircled the Japanese and severed their supply lines, leaving soldiers in some regiments with only 10 to 15 bullets each. The Eleventh Army withdrew under persistent attack, with Japanese air superiority preventing complete annihilation.
Casualty estimates vary significantly. Chinese sources put Japanese losses at nearly 57,000, including 33,941 killed and 23,003 wounded, though Chiang Kai-Shek called these figures unrealistic. The Japanese army officially reported 1,591 killed and 4,412 wounded. The Chinese Ninth Military Front recorded 30,346 killed, wounded, or missing.
Changsha fell to Japan in 1944 during the Ichi-Go offensive. The city had been successfully defended against Japanese attack in 1939-1941, and the Third Battle of Changsha in 1941-1942. Chinese forces retook the city in 1945.
Changsha was the capital of Hunan Province and the center of China's most important rice-producing region. Those fields supplied food for the densely populated areas around Chongqing, China's wartime capital. Its successful defense in January 1942 was the only Japanese military defeat in the weeks immediately following Pearl Harbor.