Flag of Japanese Korea (I&B4) by @Thorvald (El Thorvaldo)

Japan's point of departure in Iron and Blood 4 concerned the 1597 invasion of Korea: Tokugawa Ieyasu led a rapid campaign that conquered the peninsula in six months, but was killed in battle with Ming forces at the war's end, and Toyotomi Hideyori ascended as kampaku (Imperial Regent). Unlike the first invasion in 1592, the second campaign was waged with genocidal intent against the Koreans both during and after the war: officially recognized as a Japanese vassal in the 1598 peace, in practice it was treated as a province and targeted for concerted colonization efforts; by the turn of the 18th Century, the surviving Korean population had fallen to several hundred thousand.

Under Toyotomi Hidetsugu, Japan's treaty ports were moved off the mainland to Taiwan and Korea, encouraging economic development; following the 1798–1802 civil war, Clan Hatakeyama became a member of the Second Regency Council, further enriching the peninsula before its subsequent secession attempt brought all periphery territories under direct control of Tokyo. By game's start in 1931, the native Korean population had rebounded to several million, constituting the largest minority of the empire.

Uploaded to the now-defunct IOT Wiki in 2020, replacing JohannaK's original raster.

Download submitted to DeviantArt October 2022; alternative download available via Patreon.