Why was Japan an Axial power?

Japan was considered an Axis power during World War II primarily due to its alignment with Germany and Italy, forming a military alliance aimed at expanding their territories and influence. The tripartite pact, signed in 1940, solidified this partnership, as the nations sought to oppose Allied powers. Japan's expansionist agenda in Asia and the Pacific, including its invasion of China and attack on Pearl Harbor, further demonstrated its commitment to the Axis cause. This collaboration was rooted in shared interests in territorial expansion, militarism, and opposition to communism.