<human>:  Why did the Japanese lose in the Battle of Nanking?
<bot>: The Japanese army was outnumbered by the Chinese army by about 10 to 1. This meant that the Japanese army was unable to attack the Chinese army head on. Instead, they had to choose a different tactic. They surrounded the Chinese army and cut off their supplies, starving them out. This tactic worked well, and the Japanese army was able to defeat the Chinese army.