China believed the initial Japanese attack in Ichi-Go to be a localized feint in northern China, so 400,000 troops in Northern China were deliberately withdrawn without a fight in the face of the Japanese advance. The initial force of 30,000 Japanese troops soon grew to number several hundred thousand, and the Chinese defensive line collapsed as the offensive pressed into Central and South China. However, a contingent of 17,000 Chinese held Hengyang against over 110,000 Japanese soldiers in what would become the longest siege of the war.