The first painting work recorded as having been done by Masanobu is the screen paintings he did of the Deity of Mercy and Luohan in Unchoin, Shokoku-ji Temple Tower, which he did in Kyoto at the age of 30 in 1463. This was just before the turmoil of the Onin War (1467 - 1477) (as reported in Inryoken Nichiroku (Inryoken's Diary)), which tells us that Masanobu was already working as a painter in Kyoto by that time.
正信の画業として記録に残る最初の事例は、応仁の乱（1467-1477）の直前の寛正4年（1463年）、30歳の時に京都の雲頂院（相国寺塔頭）に観音と羅漢図の壁画を制作したというもので（『蔭涼軒日録』所載）、この時点で正信がすでに京都において画家として活動していたことがわかる。