Sano Masakoto

Sano Masakoto (佐野 政言, 1757 – 1784), nicknamed Sano Zenzaemon (佐野善左衛門) was a Japanese samurai, a hatamoto guard of Edo Castle, who gained his fame by killing the unpopular wakadoshiyori Tanuma Okitomo [ja] in March 1784 in the castle.

On March 24, 1784, in Edo castle, Sano shouted three times "remember", Oboegaaro (覚えがあろう) to Tanuma Okitomo and cut him with a wakizashi.

The exact motive of Sano remains unclear and there are several competing theories, but the shogunate put his actions on a moment of madness.

This sudden shift was put on Sano's actions, who was deified as Yonaoshi Daimyojin (世直し大明神, great patron of world renewal).

The campus of Otsuka Women's University in Sanbanchō is on the site of his residence, which is marked by a touristic sign.