Photo/IllutrationApparent explosives surrounded by fishing nets were found in waters off Tateyama, Chiba Prefecture. (Provided by Hiroyuki Arakawa)

  • Photo/Illustraion
  • Photo/Illustraion

TATEYAMA, Chiba Prefecture--An elderly diver has found the apparent remains of Shinyo kamikaze motorboats that were dumped into the sea after the end of World War II.

Hiroyuki Arakawa, 79, who runs the Hasama Kaichukoen diving company, discovered a 1-meter-long engine, a metal piece 30 centimeters in diameter resembling a propeller, and what appears to be explosives on the seabed about 1 kilometer northwest of the Hasama fishing port in Tateyama.

Arakawa was diving 32 meters deep when he found the items about six months ago.

Toward the end of World War II, Hasama hosted a base for the No. 59 Shinyo unit tasked with using the boats for suicide missions against U.S. ships.

Thinking that the remnants may be Shinyo boats, Arakawa explained his discovery to a friend in the media, who then contacted a former driver of the kamikaze boats.

The former sailor said the remains “are no doubt from Shinyo.”

The motorboats, developed by the Imperial Japanese Navy, were loaded with 250 kilograms of explosives in the bow and were powered by engines based on those for trucks.

Their bodies were made from plywood, leaving them vulnerable to damage. Many Shinyo were unable to reach the enemy vessels.

But the pieces found by Arakawa seem to have come from boats that survived the war.

Katsumi Muto, 88, who lives in Saitama’s Kita Ward, was one of the 176 servicemen in the No. 59 Shinyo unit. Tasked with maintenance of the boats, Muto said he was ordered by a superior officer to sink the Shinyo immediately after the war ended.

He said he brought about 20 Shinyo to waters off Tateyama, drilled holes in the ship bottom and sank them. He then joined efforts to dismantle the base.

“I cannot clearly remember where I sank them, but the remains may be part of the Shinyo,” Muto told The Asahi Shimbun. “I was overcome with emotion to hear they might still lie in the waters even after more than 70 years.”

More than 6,000 Shinyo were built and deployed to the Philippines and elsewhere outside Japan, as well as to the Boso Peninsula in Chiba Prefecture and other places in Japan. They were to be used for “hondo kessen” (decisive fighting on the mainland).

Fifty-three single-seater Shinyo, each 5 meters long, and five 6.5-meter-long two-seaters were to be deployed to the base in Hasama.

A concrete ramp was set up on the coast to launch the motorboats for their suicide missions. Part of those facilities still remain.

Records from the Defense Ministry’s National Institute for Defense Studies showed that underground warehouses to store Shinyo, fuel, food and other materials were constructed at the base.

U.S. military records show that nine Shinyo in the underground warehouses were seized in Hasama, while two sunken Shinyo were recovered there.

“If the findings are really the remains of Shinyo, I feel like a legacy that has historically been shrouded in secrecy has finally been brought to light,” said Emiko Ikeda, secretary-general of the nonprofit group Awa Cultural Heritage Forum, which studies war relics in Tateyama.

“We should squarely accept the fact that part of the nation’s history of aggression has been revealed and pass on the stories to the next generation.”

Arakawa said he is currently seeking “people who can store the remnants to commemorate the soldiers who died in the war,” and he will provide assistance for the recovery efforts in the sea.