Four men broke into a pachinko parlor in Gifu Prefecture early Monday and made off with 33 million yen after threatening the manager with a pistol and knives, police said.
The 45-year-old manager and three employees were not injured, police said.
The intruders wore dark clothing and caps pulled down low to hide their faces, according to police.
The men stormed in through the back door after the parlor had closed and the employees were cleaning up, they said.
They spoke to the employees in broken Japanese and communicated among themselves in what sounded like Chinese, police quoted the employees as saying.