The municipal government of Ishigaki in Okinawa Prefecture has conducted a marine investigation around the Senkaku Islands to collect data for environmental conservation.
Conducted on Monday, it was believed to be the first full-scale survey by an administrative organization since the one conducted by the Tokyo metropolitan government in 2012, just before the islands were nationalized.
Two vessels of the China Coast Guard intruded into Japan's territorial waters and approached the investigation ship on Monday, but there was no contact or other accidents.
