The victim had just finished dining at a restaurant and was walking through one of Japan's most popular tourist destinations as part of a group tour when the altercation occurred, according to Japan Today newspaper.
The suspect reportedly stabbed him during the confrontation.
The victim was rushed to a nearby hospital for treatment. His condition has not been disclosed.
Kyodo News reported that the suspect is approximately 1.75 meters tall, wore glasses, and was last seen in a white T-shirt.
Authorities believe the suspect and victim reportedly did not know each other.
Police are treating the case as attempted murder and are continuing the search for the suspect.