In addition, Mitsuhide sent a letter to Shigeharu TSUCHIBASHI, who was a member of the Saigashu (a powerful local clan in Saiga, Kishu), saying, 'A joi (order from a superior to a subordinate) has been issued requesting that you provide service, which is a great honor', and Fujita pointed out that as the word 'joi' was used, the order must be from someone with a higher status than Mitsuhide.
加えて本能寺の変直後、光秀が紀州雑賀衆・土橋重治へ送った書状に「上意馳走申しつけられて示し給い、快然に候」と、光秀より身分の高い者からの命令を指す「上意」という言葉を使っていることを挙げ、光秀の背後に足利義昭が存在したと主張している。