The 300 million yen robbery (三億円事件, San Oku En Jiken), also known as the 300 million yen affair or incident, was a robbery that occurred on December 10, 1968 in Tokyo, Japan. A man posing as a police officer on a motorcycle stopped bank employees transferring money and stole 294 million yen. It was the single largest heist in Japanese history at the time. Half a century later, the case remains unsolved.