Guam is declared secure; 7,500 Japanese troops are still loose in the hills
Guam had belonged to Japan since three days after the attack on Pearl Harbor, when Japanese forces captured the island on 10 December 1941, and taking it back would give American bombers the airfields needed to reach the Japanese home islands. On 21 July 1944, the 3rd Marine Division landed at Asan and the 1st Provisional Marine Brigade landed near Agat, on opposite sides of the Orote Peninsula, with landing craft stopped short by a reef hundreds of yards from shore. Japanese defenders under Lieutenant General Takeshi Takashina fought from the peninsula and then withdrew into Guam's mountainous interior. On 10 August, organized resistance ended, though some 7,500 Japanese soldiers remained scattered across the island.
Guam had been American territory since 1898 and fell to Japan just three days after Pearl Harbor, making its recapture personal as well as strategic. Its airfields gave the Army Air Forces the runway length needed to fly B-29 Superfortresses against Japan itself, and became the launch point for the war's final campaign against the home islands.
QWhat happened to the American sailors who evaded capture when Guam fell in 1941?
Six US Navy sailors slipped away into the jungle rather than surrender when Japan seized Guam on 10 December 1941. Five were eventually tracked down by Japanese search parties and executed. The sixth, George Tweed, stayed hidden for the entire occupation, sheltered by Chamorro islanders who risked their own lives to feed and hide him. Tweed remained at large for over two and a half years, surviving until American forces returned in July 1944. His survival stood in stark contrast to the fate of the Chamorro population, thousands of whom Japanese troops forcibly marched into internment camps like Manenggon as the invasion approached.
QWhy did a Japanese submarine attack accidentally strand an entire infantry regiment on Saipan instead of Guam?
On 29 February 1944, the American submarine USS Trout torpedoed and sank the Sakito Maru, a transport carrying 4,124 Japanese troops of the 29th Division toward the Marianas, including most of the 18th Infantry Regiment. Escorting destroyers depth-charged Trout in retaliation, sinking it with its entire crew, but they also diverted to pick up 1,620 survivors and dropped them at Saipan instead of continuing to Guam. The regiment's 1st Battalion never made it to its intended destination, permanently altering the troop distribution the Japanese had planned for Guam's defense.
QHow badly did prewar American maps of Guam actually fail the invading troops?
Despite Guam being a US possession since 1898, the Office of Naval Intelligence's 345-page study and the 1:20,000 maps issued to troops in 1944 were riddled with errors. Contour lines were broken, indicating the terrain had never been properly surveyed, and roads marked on the maps, especially in the north, frequently did not match reality. Areas labeled bare on paper turned out to be dense forest, and low hills went unmarked entirely. The Japanese defenders, by contrast, had better maps of the island than the Americans returning to reclaim their own territory. Planners tried to compensate with plaster relief maps built at double vertical exaggeration and submarine reconnaissance photos taken by USS Greenling in April.
