Japan seizes Manchuria

Japan takes advantage of the chaos in the world and annexes Manchuria.

Japan was the youngest member of the club of world powers. It's process of westernization was still ongoing (while being the only case of it to truly succeed in the world's history), and while it was a regional power, it still had greater ambitions. It already managed to defeat Russia in 1905 war. Now, it was the time to progress a bit further.   Manchuria was already excluded from Russian zone of influence following its defeat in 1905 war. It was officially a territory of the Republic of China, but one that it could barely control, especially now when it was nearing an open civil war. With the attention of Entente moving more and more to the Europe, and the Russian Republic having much more important problems in the west, Japan decided to make a move for Manchuria.   Instead of conquering it openly, which wasn't a viable strategy, Japan simply started buying local warlords. With Republic of China being essentially a ruin of a state, it couldn't react properly (and, besides, Manchukuo wasn't part of 'real' China. It, however, caused sudden spike of nationalism in China.