However, after Akitsuna UTSUNOMIYA died, not only Mochitsuna but also Masatuna decided to inherit the head family of the UTSUNOMIYA clan, and therefore, the MUMO clan was taken over by the third son of Masatsuna.
しかしその正綱も宇都宮明綱の死後、宇都宮宗家を継いだため正綱の三男の武茂兼綱が武茂氏を継ぐ。