Answer: Japan felt its hand was being forced
Explanation:
At the time that Japan joined the Axis powers it was in a war with China to expand its power and collect resources ever since 1937. This war was looked down upon by France, Britain, and the US. Japan saw this as a threat and more evidence that they would not be treated as an equal from the allied powers. After this realization Japan began making allies with other countries and immediately befriended Germany and Italy. Soon after Italy joined the axis powers and France was nearly fully taken over. Japan saw this as an immediate threat in the case that Germany could possibly wage war in Japan. Seeing as Japan was already allied with Italy and Japan feared future attacks from Germany, Japan joined the Axis powers.