Kohama Island Shinyō Boat Tunnels
Taketomi Town, Okinawa Prefecture
The small island of Kohama, part of the Yaeyama Islands east of Taiwan, is located between Ishigakijima and Iriomotejima.
Kohama has four tunnels that were constructed near the end of World War II to
hide shinyō explosive motorboats that the Japanese Navy planned to use in
suicide attacks against Allied ships if they approached the island.
The shinyō boat tunnels can be reached by walking east along the beach from
the ferry terminal a little more than a kilometer. The tourist guide map for the
Kohama Island marks the location of the tunnels, but there is no sign to provide
any historical information regarding them.
The entrance to the first tunnel can be seen easily from the beach. The
entrances to the other three tunnels are somewhat hidden by heavy undergrowth.
The tunnels were constructed in a cliff near the beach and are about 25 meters
The first three tunnels from the beach remain in good condition about 70
years after they were constructed. In comparison to the second and third tunnels
from the beach, the first tunnel has quite a bit of rubbish inside, probably due
to its easy access from the beach. In contrast to the first three tunnels, the fourth tunnel is almost
completely filled at the entrance with rubble, sand, and rocks, so it cannot be
View from entrance of first shinyō boat tunnel from beach
The 38th Shinyō Special Attack Squadron was stationed first at
Kohama, but it was later reassigned to Miyara Bay on Ishigakijima. The 38th
Shinyō Squadron only trained once at Kohama during the night, but it could not
continue due to the constant threat of enemy air attacks. The 26th Shinyō
Special Attack Squadron, which arrived at Ishigakijima on March 1, 1945, was
stationed at Kohama Island until the end of the war.
View from entrance of second shinyō boat tunnel from beach
From September 16 to October 21, 1944, the 50 shinyō boat pilots in the 26th
Shinyō Special Attack Squadron trained in Nagasaki Prefecture at the Kawatana Torpedo Boat Training
School. The pilots were selected from the 13th Kōh Class of the Yokaren
(Preparatory Flight Training Program) from Nara Naval Air Group. In addition to the 50
shinyō boat pilots, the 26th Shinyō Squadron had 7 officers, 18 headquarters
personnel, 35 maintenance workers, and 74 base workers for a total of 184
View from entrance of third shinyō boat tunnel from beach
The 26th Shinyō Special Attack Squadron
officially formed on December 5, 1944. The squadron had 52 one-man Model 1
shinyō motorboats loaded with explosives for suicide attacks to crash into enemy
ships. The Pacific War ended without the shinyō squadron's boats ever making a
sortie to attack.
View from entrance of fourth shinyō boat tunnel from beach
On September 13, 1945, when returning to the mainland after the
end of World War II, 26th Shinyō Squadron Commander Lieutenant Junior Grade
Yūji Hikino, one shinyō boat pilot, and one maintenance worker lost their lives
due to heavy wind and rain. Five 26th Shinyō Squadron members in total lost
their lives during the war.
View of sea from beach next to first shinyō boat tunnel
The section on the 26th Shinyō Squadron in the two-volume
history of the Shinyō Special Attack Corps published in 1990 by the Shinyō
Association has a photograph of a monument inside of one of the tunnels to
remember squadron members who died in the war .
However, during a visit to Kohama Island in November 2013, there were no traces of the monument that could be found.
The historical information about the 26th Shinyō Special
Attack Squadron is from pages 56-7 of the following book:
Shinyō Association (Shinyōkai), ed. 1990. Ningen heiki:
Shinyō tokubetsu kōgekitai (Human weapon: Shinyō Special Attack
Corps). Shiro Arai, general editor. Volume 2 of 2. Tokyo: Kokushokankokai.
The historical information about the 38th Shinyō Special
Attack Squadron is from pages 80-1 of the book.
1. Shinyō Association 1990, Volume 2, 57.