Forty-five meters beneath the Pacific, Kingo Wakasa hovers beside the rusted hull of a World War II war grave off northern Okinawa.

The ship below is the USS Emmons, an American destroyer scuttled on April 6, 1945, after taking five Japanese kamikaze strikes near Kouri Island. It rests on the seabed alongside the engines and shattered metal of the attacking aircraft.

For Wakasa, a 56-year-old technical wreck diver from Tokyo, the site carries profound personal weight: It represents the very war effort in which his grandfather served as an officer. After roughly 950 dives — 250 of them on the Emmons — he still regularly descends to map unrecorded artifacts before seawater destroys what remains.