In May 1555, Tatsunari (changed name from Nobuyuki) started to claim kanto (government service) of danjo no jo (a post named "jo" [referring to a judge] in the "Danjo" [referring to the Ministry of Justice]), which was claimed by family head for generations, over the head of Nobunaga and he became the only opponent of Nobunaga in the family.
天文24年（1555年）5月頃、達成（信行から改名）は代々の当主が名乗ってきた弾正忠の官途を信長を差し置いて名乗るようになり、家中で信長の唯一の対抗者となっていった。