Kohama Island Shin'yō 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 shin'yō explosive motorboats that the Japanese Navy planned to use in
suicide attacks against Allied ships if they approached the island.
The shin'yō 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 shin'yō boat tunnel from beach
The 38th Shin'yō Special Attack Squadron was stationed first at
Kohama, but it was later reassigned to Miyara Bay on Ishigakijima. The 38th
Shin'yō 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 Shin'yō
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 shin'yō boat tunnel from beach
From September 16 to October 21, 1944, the 50 shin'yō boat pilots in the 26th
Shin'yō Special Attack Squadron trained in Nagasaki Prefecture at the Kawatana Torpedo Boat Training
School. The pilots were selected from the 13th Kō Class of the Yokaren
(Preparatory Flight Training Program) from Nara Naval Air Group. In addition to the 50
shin'yō boat pilots, the 26th Shin'yō Squadron had 7 officers, 18 headquarters
personnel, 35 maintenance workers, and 74 base workers for a total of 184
View from entrance of third shin'yō boat tunnel from beach
The 26th Shin'yō Special Attack Squadron
officially formed on December 5, 1944. The squadron had 52 one-man Model 1
shin'yō motorboats loaded with explosives for suicide attacks to crash into enemy
ships. The Pacific War ended without the shin'yō squadron's boats ever making a
sortie to attack.
View from entrance of fourth shin'yō boat tunnel from beach
On September 13, 1945, when returning to the mainland after the
end of World War II, 26th Shin'yō Squadron Commander Lieutenant Junior Grade Yūji Hikino, one
shin'yō boat pilot, and one maintenance worker lost their lives
due to heavy wind and rain. Five 26th Shin'yō Squadron members in total lost
their lives during the war.
View of sea from beach next to first shin'yō boat tunnel
The section on the 26th Shin'yō Squadron in the two-volume
history of the Shin'yō Special Attack Corps published in 1990 by the Shin'yō
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 Shin'yō Special
Attack Squadron is from pages 56-7 of the following book:
Shin'yō Association (Shin'yōkai), ed. 1990. Ningen heiki:
Shin'yō tokubetsu kōgekitai (Human weapon: Shin'yō Special Attack
Corps). Shirō Arai, general editor. Two volumes. Tōkyō: Kokushokankōkai.
The historical information about the 38th Shin'yō Special
Attack Squadron is from pages 80-1 of the book.
1. Shin'yō Association 1990, Volume 2, 57.