Japan

Japan is a important nation in a lot of Turtledove book.

Japan in Southern Victory
As in OTL Japan fought for the Entente during the Great War but eventually pull out of war. There a bit smaller than what we had as it doesn't have control any part of China or Shakaline island, but still Timeline-191 Japan hold Vietnam, Taiwan, Korea and Indonesia. It mostly fight with the United States for the control of Sandwich Islands (OTL Hawaii)

Japan in WorldWar
Was one of the few free nation remaining after the race invasion.

Japan in Day of Infamy
Mostly the same apart from the fact that's it's was able to pull out an invasion of Hawaii in 1941.