The following year, 940, he was designated Seito-taishogun (literally, "great general who subdues the eastern barbarians") to quell the war in Kanto (eastern Japan) staged by TAIRA no Masakado, but before he arrived, Masakado was killed.
翌940年（天慶3年）関東で乱を起した平将門を追討するため征東大将軍に任じられたが、関東に到着する前に将門は討たれていた。