A Japanese man stabbed himself in the stomach outside Japan's parliament building on Monday, police and ambulance services said, in an apparent suicide attempt by ritual seppuku disembowelment.
"We are now investigating his motivation," a police spokesman said.
"The injured man was taken to hospital immediately," said a spokesman for Tokyo emergency services.
Japan's Jiji Press said the man, 39, had survived and appeared to be a member of a right-wing nationalist group.
Japan faces a general election on August 30.
Seppuku is a form of ritualistic suicide once practiced by samurai warriors.