@Alexandre le Grrrand,

Korea was the battlefield of Seven Year War in Toyotomi Hideyoshi's invasion plan to China. The Devil General Kato Kiyomasa and his brave actions in Korea. The famous turtle warships used by Korean navy. The Battle of Haengju with both side heavy casualties. All these happened before the battle of Sekigahara in 1600.

So, your Mod is focused in Japan islands only. From what year to what year?