'Bleacher' was the US geographical rather than operational codename for Tongatabu, largest of the islands constituting the Tonga archipelago (1941/45).

Tonga is a large island group in the South Pacific Ocean about 3,000 miles (4830 km) to the south-west of Pearl Harbor in the Hawaiian islands group. There are 169 islands in the group, most of them uninhabited, with a total land area of about 289 sq miles (748 km²), with a 1941 population of about 35,000 persons, almost half of them in the southern group including Tongatabu. Most of the inhabitants were native Polynesians, and there were also about 1,300 Europeans, Chinese and others.

Extending about 500 miles (805 km) along a north/south axis, the islands are located far enough to the south to possess a pleasant climate with distinct warm and cool seasons. However, the islands are vulnerable to typhoons from October to April.

In 1941 Tonga was a British protectorate and the only constitutional democracy in Polynesia. In 1942 Tonga was ruled by Queen Salote Tupou, who declared war on Germany and then Japan at the suggestion of the British.

There was a good port and airfield at Nuku’Alofa on Tongatabu, which later became 'Edit' and then 'Verulam', where the US Navy began the development of an advance fleet base in early 1942.

In 1939 the country raised the Tonga Defence Force, which grew to 2,000 regulars and was incorporated into the New Zealand 16^th Brigade Group, as well as a 2,000-man home guard trained and equipped by New Zealand. Coastwatching stations were estab­lished throughout the islands and some Tongan troops saw combat in the Fiji Regiment and the Fiji Guerrillas.

Early in 1942, the utility of Tongatabu’s as a naval fuelling station came to be appreciated as an al­ternate staging point for aircraft en route from the USA to Australia and New Zealand, and as an air base supporting operations to the south of the Samoa and Fiji island groups. An agreement was negotiated through the British consul, and US defence and construction forces started to arrive on 9 May 1942. The reinforced 147^th Infantry, 77^th Coast Artillery (Anti-Aircraft) and 68^th Pursuit Squadron, in all some 7,800 troops, and more than 800 US Navy base and construction troops garrisoned the island. US planners felt that the Japanese would not attempt to land major forces in the Tonga islands group, so this defence force was seen as adequate to cope with raids and perhaps dissuade the Japanese from landing in force during their expected move to the south on New Caledonia and the Fiji and Samoa island groups. The US Navy constructed a seaplane base, refuelling depot, and for the US Army camps, support facilities, and gun emplacements. Con­tractors built a three-runway airfield for the US Army near Fua’amotu on the south-eastern tip of the island.

Members of the local population were employed extensively as stevedores and labourers. The naval base never operated to full capacity, but had the USA been defeated in the 'Battle of the Coral Sea' during May 1942 and the Japanese had then opted to advance on New Caledonia and the Fiji and Samoa island groups in 'Fs' (i) as planned after seizing Midway island, the base would have become very important.

The fleet carrier Sar­atoga and battleship North Carolina undertook emergency repairs at Tongatabu after being torpedoed in August and September 1942 respectively.

Most of the 147^th Infantry departed for Guadalcanal in November 1942 with the 2/147^th Infantry leaving at the end of January 1943. As the war moved away to the north-west, Tongatabu was the first South Pacific base to be closed, a move ordered in November 1943. The fuel depot was dismantled and moved to Wallis island. The airfield and other facilities were transferred to the New Zealand army at the end of February 1943. The 77^th Coast Artillery departed in early April. New Zealand troops had departed before the end of the war, although the airfield remained in use.