Answer;
It wanted to have more security, prestige, wealth, and power.
Step-by-step explanation;
Japan was the only Asian country to have escaped imperialist control. For centuries, military generals, called shoguns, exercised real power in Japan while the Japanese emperor was a mere figurehead.
Japan's expansion was undertaken in an environment of imperialism of European countries. Japanese expansion in Asia was undertaken in an age of active Western expansion into China.