In November 939, Masakado surrounded Hitachi Province, and kept on attacking and surrounding other provinces after that, he then placed a 'new Emperor' in Kozuke Province without permission and had a Jimoku ceremony (ceremony to appoint government officials at the Imperial Palace) of the countries in Bando, not only Tsunemoto was set free since his previous false accusation became true, but also he was awarded for his report and was appointed to Jugoinoge (Junior Fifth Rank, Lower Grade).
天慶2年（939年）11月、将門が常陸国府を占領、その後も次々と国府を襲撃・占領し、同年12月に上野国府にて「新皇」を僭称して勝手に坂東諸国の除目を行うと、以前の誣告が現実となった事によって経基は晴れて放免されるばかりか、それを功と見なされて従五位下に叙せられた。