What Was A Major Effect Of The Russo-Japanese War? Japan Added Manchuria To Its Territory. Japan Gained Influence In Nations Such As Manchuria And Korea. Russia Defeated The Japanese Fleet. Russia Rose As A Major Competitor For Power In East Asia.. Japan gained influence in nations. Russia defeated the japanese fleet.

It marked the first time in modern. Japan gained influence in nations such as manchuria and korea. Marking the first time an asian power defeated a european empire in modern warfare, this war reshaped global geopolitics and signaled japan’s rise as a major military.