Airfields - "Entaigo"
The Japanese called "entaigo" the concrete bomb shelters that could be found in many airfields in Japan mainland and also at the major airfields of Korea and Taiwan (not sure about Manchuria). They were covered with earth and vegetation and blended perfectly with the surrounding area making them particularly difficult to spot from the air. Their design varied. We visited many post-war areas where airfields used to be and the "entaigo" in every airfield were different from the other airfields. At the places we visited, locals have great difficulty destroying them, as the cost is prohibitive and therefore they are used to store agricultural equipment.
The Japanese called "entaigo" the concrete bomb shelters that could be found in many airfields in Japan mainland and also at the major airfields of Korea and Taiwan (not sure about Manchuria). They were covered with earth and vegetation and blended perfectly with the surrounding area making them particularly difficult to spot from the air. Their design varied. We visited many post-war areas where airfields used to be and the "entaigo" in every airfield were different from the other airfields. At the places we visited, locals have great difficulty destroying them, as the cost is prohibitive and therefore they are used to store agricultural equipment.
A typical "entaigo" found, I believe, in Oppama base, Yokosuka, right at the end of the war.
The top left "entaigo" with the Mitsubishi J2M "Raiden" in front of it was found at Atsugi Base, Kanagawa Prefecture, when the first US soldiers occupied the base. The other three photos were taken at Koza IJNAF Arsenal, near Atsugi, where "Raiden" were assembled and serviced. Note that the facade of the structure is partially covered with wood.
One of the first ex-airfields we ever visited, was the IJNAF base in Usa (NOT U.S.A.), Oita Prefecture, Kyushu, where a few well-preserved small "entaigo" are still standing in the middle of fields. Note the difference in the design of these two "entaigo", sheltering different types of aircraft and how well covered they still are with vegetation.
Note that in all surviving "entaigo" the facade is made of concrete.
An illustration in Usa, gives a good idea what the "entaigo" looked with the aircraft in place.
A less-often photographed "entaigo" in Usa is this huge one which probably sheltered Mitsubishi G4M "Betty" bombers.
A more adventurous visit (where a taxi driver dropped us in the middle of nowhere) was in Kochi, the capital city of Kōchi Prefecture, on the island of Shikoku, where many "entaigo" are located near the modern airport. As you can see in the photos, one of them has a small agricultural road passing through it. But there were others that were very well-preserved, like the one in the bottom three photos. The smaller "entaigo" like the ones in the photos were 5m high, 15m wide and 8m deep.
Another huge "entaigo" in Kochi for bigger bomber aircraft. This one was about 10m high, 45m wide and 22m deep.
An illustration showing where the "entaigo" (in red) were located in Kochi airfield.
Also on Shikoku Island, "entaigo" can be found in Matsuyama, Ehime Prefecture, but they are standing right in the middle of the rural area.
In Mobara, Chiba Prefecture, a number of "entaigo" of very different design are still standing.
One of them has been preserved as a historical remain of the airfield that used to be in the area. I believe its design is the same with the one in the previous photos, it just sits lower on the ground.
A short clip from a video taken in February 1946, shows the "entaigo" located in Oita airfield, Kyushu.
