The incident occurred on Monday morning during the commemoration ceremony of the 80th anniversary of the Battle of Guadalcanal, New Zealand news website Stuff reported.
The attack happened right before the laying of wreaths. Military and local volunteers standing nearby quickly neutralized the assailant. The injured was immediately treated in an ambulance and a Japanese official confirmed the fact of a light injury in the neck, the report said.
The ceremony was organized by the minister of tourism and culture of Solomon Islands, Bartholomew Parapolo. Japanese Deputy Defense Minister Makoto Oniki and New Zealand Defense Minister Peeni Henare attended the ceremony alongside Sherman.
A video of the incident has emerged online.
The ceremony resumed after a 10-minute pause. Locals and senior officials conveyed their apologies to the guests.
"I sincerely apologise for the unexpected and disappointing event," the Solomon Islands permanent secretary for tourism, Bunyan Sivaro, said, as quoted in the report.
The Solomon Islands law enforcement agencies have launched an investigation into the incident and the attacker is now in custody, according to local newspaper Solomon Star.