At just past midnight on Monday, Akiyoshi Ishiyama, 56, is alleged to have jumped atop the man, 46, atop a road and repeatedly slammed his head against the pavement.
The victim was rushed to a hospital where he remains unconscious, police said.
Upon his arrest on suspicion of inflicting injury, Ishiyama admitted to the allegations, police said.
According to police, Ishiyama, who was drunk at the time, was not acquainted with the victim.
Prior to the incident, Ishiyama kicked over a pylon at a construction. The victim then warned him. “I got angry after [he] warned me,” the suspect told police.
