History
Prior to the war, Japan developed the island into a Navy base begining in November 1940, that including a HQ building, eight barracks, five garages, and sick bay. The island was built up as a naval base, supported by a large Japanese community complete with trade stores, restaurants, geisha houses.

Fourth Fleet HQ was built in November 1943 a large central concrete building, three others large and nine smaller buildings. Facilities were manned by the 41st Naval Guard Unit. Forth Fleet Hospital could care for 850 patients in 5 wards and 24 other smaller buildings. 12 Concrete water reservoirs, an ice house, dental clinic, pharmacy, three warehouses and research lab existed. Naval Construction Department included 10,000 men at its peak.

The main radio station of the five in the islands was located at Dublon, where several concrete receivers shelters and buildings were constructed. Forth Harbor Department was located on the southeastern part of the island near Doblon Town. It was 22 wooden buildings including repair shops, warehouses and barracks.

South Seas Development Company had docking facilities on the southwestern tip of the island. Its supply storage and fish cannery were commandeered by the Navy, and it became the Fourth Naval Dockyard. It was the main receiving area for the military. More warehouses and a refrigeration building, HQ, and a two story barracks were constructed. A thousand men worked here on ship repairs, mostly damage sustained to ships from American submarine attacks. The facility also had a 30 ton floating crane and 2,500 ton dry dock. Nearby was a sawmill, and small rail cars connected most of the buildings.

The Truk Transportation department loaded and unloaded supplies from ships. Since there were no docks for the larger ships, supplies needed to be ferried to the bigger ships. Truk's marine infrastructure was second rate, and was capable of properly servicing a modern Naval fleet. A derrick, carts, 40 trucks, barges, harbor craft, tugs and sampans were used for these purposes.

Japanese Army's 52nd "Oak" Division
The Army's 52nd Division arrived in Truk from November 1943 to January 1944. There were not enough buildings for the troops and they were forced to camp in tents, and in civilian houses and schools. These Army troops were cut off from supply after they arrived and had to rely on the Navy for supplies and equipment. They built most of the land based defenses on the islands, most were based on Dublon

Today
Today, the island is known as Tonoas Island. The jungle has swallowed up the remains of these places. The hospital are easy to locate, as are water and fuel storage tanks, and signposts written in Japanese. Caves and tunnels are rumored to exist in the cliffs filled with supplies, war materials and ammunition. Others contain hidden coastal defenses and AA guns.

85th Submarine Base
On the western shore was the 85th Submarine base, constructed in May 1942. It serviced, supplied and did minor repairs to subs. Torpedoes were stored in caves and transported by rail car to the shore. Many different repair and barracks existed specific to submarines.

Japanese Grave Markers

Dick Williams Dick Williams reports: "This is a grave marker for Japanese military personnel. The marker reads from top to bottom ka-i-gu-ng-po-chi. Translation: Navy Graves. The marker about 6" hi as I recall, steps to the right of it lead to the top of a hill where a platform about 10x30 feet of concrete resides. There was a spot for incense and flowers. One must remember that the Japanese, when they obtained Truk, colonized it. A Japanese man could marry a Micronesian woman, but NEVER vice-versa. So, a lot of people I knew were 1/4 or 1/2 Japanese, and spoke Japanese fluently. At wars end, all the Japanese men were repatriated without their family. Many, many broken homes."