Minamoto no Masanobu/Masazane (源 雅信) (920–993), third son of Imperial Prince Atsumi (son of Emperor Uda), a Kugyō (Japanese noble) of the Heian period.
At first he disputed his daughter's marriage because of Michinaga's position, but his wife Bokushi (穆子) pushed for the marriage.
Finally Michinaga became regent of the Emperor, so his wife was redeemed as a good judge of character.
Michinaga came into Masazane's residence Tsuchimikado-dono (土御門殿).
He is the progenitor of the Uda Genji (宇多源氏).