 In 1352, he helped lead Loyalist forces in the capture of Kyoto.In 1353, as Yamana Tokiuji, a recent convert to the loyalist cause, approached the capital, Masanori led a force to seize certain neighboring areas such as Tennōji and Yahata, while other forces mobilized in other directions.In July of that year, he pressed north from Yahata, towards Kyoto, burning towns as he went, while Yamana approached from Nishiyama to the west of the city.