That is to say, Hideyoshi hoped to be promoted to Sadaijin instead of Udaijin, if possible, because his master, Nobunaga, was killed by Mitsuhide with the title of Udaijin as his highest rank and thus serving as Udaijin would be a bad omen.
理由は「主君であった信長は右大臣を極官として光秀に殺害されており、右大臣は縁起が悪いので出来るならば右大臣は避けて左大臣への昇進をお願いしたい」というものであった。