Masahisa Takenaka (?? ??, November 30, 1933 – January 27, 1985) was the short-lived 4th kumicho of the Yamaguchi-gumi, Japan's largest yakuza gang.
He took the role of kumicho (supreme Godfather) in 1984, but was assassinated at a girlfriend's home in Osaka early the next year by a rival faction, the Ichiwa-kai.
The killing sparked a massive yakuza war, the Yama-Ichi War, in which more than 20 people died.