Japan's expansion into China during World War II was primarily driven by its ambitions for territorial conquest and resource acquisition. Faced with limited natural resources, Japan sought to secure access to China's vast resources, such as oil and minerals, to fuel its growing militaristic agenda. This expansion was also motivated by a desire to establish regional dominance in Asia, reflecting a broader imperialistic ideology. The invasion of Manchuria in 1931 and subsequent military actions were part of Japan's strategy to expand its empire and assert its power, contributing to the broader conflicts of the war.