Mongol invasions of Sakhalin
From 1264 to 1308, the Mongol Empire (and its successor the Yuan dynasty) made several incursions into the island of Sakhalin off the east coast of Siberia to aid their Nivkh allies against the Ainu, who had been expanding north from Hokkaido. The Ainu put up a tenacious resistance, even launching a counter-attack on Mongol positions on the continent across the Strait of Tartary in 1297, but finally capitulated to the successive Yuan dynasty in 1308.
Source: Wikipedia — Mongol invasions of Sakhalin (CC BY-SA 4.0)