Army Lt. General Simon Buckner, commander of the Okinawa operation, took an interest in observing the 8th Marines as this was their first time in action on Okinawa since the regiment entered the lines in the drive to the south. Buckner went to a forward observation post on 18 June, watching the 8th Marines advance along the valley floor. Japanese gunners on the opposite ridge saw the official party and opened up. Shells struck the nearby coral outcrop, driving a lethal splinter into the general's chest. He died in 10 minutes, one of the few senior U.S. officers to be killed in action throughout World War II. Marine General Geiger took over, declaring organized resistance on the island over on 21 June. The first battalion 8th Marine regiment suffered its last combat death of World War II the next day on 22 June 1945.