Japan had sought to claim sovereignty over Taiwan (known to them as ) since 1592, when Toyotomi Hideyoshi undertook a policy of overseas expansion and extending Japanese influence southward and westward. To the west, Japan invaded Korea in that time period, with the eventual conquest of China contemplated. To the south an initial attempt to invade Taiwan and subsequent sporadic invasion attempts spanning three centuries were unsuccessful due mainly to disease and attacks by aborigines on the island.