January - December 1944, Drive to the Philippines

The Chiyo Maru sinking into the Yellow Sea of the coast of China after a deck gun attack by the USS Tambor (SS 198) circa 1944.

Overview:

In 1944, the Allies elected to divide their ground, naval, and air forces along two strategic lines, each directed at the Japanese homeland. General MacArthur consolidated his hold on New Guinea and directed his forces north toward the strategically vital Philippine Islands. From here Allied planners hoped to continue their leap-frog north toward Formosa and mainland Japan. Admiral Nimitz and his naval forces drove across the central Pacific toward the Marianas. From island airfields on Guam and Saipan B-29 bombers could reach Japan. Along each route, the Japanese sought to reinforce lonely island garrisons with fresh men and material. This burden would fall largely on the Japanese merchant marine.

Attacked mercilessly by the Allies, Japan lost 925 merchant vessels in 1944. Each vessel averaged over 4,090 tons, amounting to a total shipping loss of over 3,796,000 tons. Allied submarines accounted for 543 of these merchantmen, totaling over 2,391,000 tons of shipping. The Allies launched massive operations codenamed Hailstone, Desecrate One, Forager which cut Japanese supply lines and isolated Japanese garrisons in the central Pacific. The Allied invasion of Morotai Island further eroded Japanese shipping lanes and completed the isolation of these garrisons from, and set up the Allied invasion of the Philippines in October 1944.

The War in the Pacific was fought by Allied forces, not American forces alone. In 1944, Allied forces other than the United States (China, Great Britain, Australia, and the Netherlands) were credited with sinking 33 Japanese merchant ships, totaling 63,308 tons.

January to September 1944:

Density study of Japanese merchant vessels sunk by the allies between January - September 1944.

Expanded Legend:

Within the South China Sea region bounded by Formosa, Luzon, Hainan, Borneo, and Malaysia, extended several Japanese shipping lanes. Used to transport oil and supplies from resource-rich Indonesian ports such as Singapore, the paths in the South China Sea became a killing field for Japanese merchantmen. Of the 668 Japanese merchantmen sunk in between Jan-Sept 1944, 21% were sunk in this territory. Of these merchant vessels, 29 were oil-laden tankers, critical for supplying the Japanese war machine with oil. Of the total merchantmen sunk here, submarines accounted for almost 70%. The majority of the sinkings occurred prior to the landing of American forces on Leyte, with 114 vessels sunk before to October 20.
The territorial waters south and west of Manilla offered the opportunity for Japanese merchantmen to move along the coasts of multiple islands, winding their way to or from their destinations. Within these waters 19 merchant were lost.
The Allies sunk 29 merchant vessels around the island of Palau in support of the Mariana and Palau Islands and the Western New Guinea campaigns. Allied aircraft sunk 22 merchant vessels on 30 March during Operation Desecrate One.
U.S. forces isolated the Japanese garrison at Guam and the North Mariana islands. U.S submarines and naval aircraft sunk 37 merchant vessels during intermittent raids between February and June 1944. Allied aircraft sent 11 to the bottom on a single day, 12 June 1944 in support of Operation Forager.
On 17 February, Allied forces struck against the Japanese bastion of Truk. Codenamed Operation Hailstone, the raid on the Japanese harbored within and near Truk lagoon resulted in 32 Japanese merchant vessels sunk. Of these, all but one were sunk by Navy carrier-based aircraft. Only one vessel, the Gyoten Maru, was sunk by a submarine during the operation. These vessels comprised approximately 200,000 tons of shipping.
The Allies continued their isolation of the Japanese garrison at the port of Rabaul and New Britain. Naval and land-based aircraft sunk 27 merchant vessels during multiple air raids in January and February.
U.S. submarines and Army Air Force aircraft sunk 14 merchant vessels between February and August in preparation for and support of the Allied invasion of Morotai Island. Allied seizure of Morotai closed off Japanese littoral shipping lanes southeast of the Philippine archipelago and east of the island of Borneo.
U.S. submarines and naval aircraft sunk 44 vessels around the Philippine islands of the Visayas, and Mindanao. Naval carrier-based aircraft sunk 18 vessels during air raids on 12 and 24 September 1944. These raids effectively ended Japanese shipping traffic south of the island of Mindanao.

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The Nagisan Maru burns as a result of an air raid during Operation Desecrate One, 30 March 1944.

Aerial reconnaissance photo of Japanese facilities at Truk, taken by a Marine Corps PB4Y-1 patrol bomber, from Bougainville, on 4 February 1944. Dublon Island is at bottom left, and Fefan Island is in lower right. In center is the Eten Island Air Base. Two aircraft carriers are visible at right, and several other warships and merchant vessels are present.

Japanese merchant ship sinking, after her back was broken by one of USS Thresher (SS 200) torpedoes, probably on 15 January or 27 January 1944.

Skipper of the USS Gudgeon (SS-211), Lieutenant Commander R.A. Bonin. He and his crew perished when the Gudgeon lost due to unknown causes sometime between April and June 1944.

October to December 1944:

Heatmap of Japanese merchant vessels sunk between October- December 1944

Expanded Legend:

The Allies continue their methodical destruction of Japanese shipping in the South China Sea and Luzon Strait. U.S. submarines sunk 129 merchant vessels between October and December 1944. U.S. navy carrier-based aircraft destroyed 25 vessels in and around the port of Manilla during a series of air raids between 13 and 19 November in support of the invasion of Leyte.
U.S. submarines and aircraft continued their assault on Japanese coastal shipping southwest of the Philippines and off the coast of Borneo. U.S. forces sunk 34 vessels between October and December 1944, 14 of which were tankers.
U.S. Army, Marine and Naval aircraft destroyed 20 Japanese merchant vessels between November and December 1944 in support of the Allied invasion of the island of Leyte.

Commander T.B. Oakley, Jr, skipper of the USS Growler (SS-215). Commander Oakley and his crew perished on 8 November 1944 off the coast the Philippines during the Growler’s 11 patrol.

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USS Growler (SS-215) seen off the coast Connecticut, on 21 February 1942.

Four Japanese merchant-type ships under attack by Task Force 38 planes off the north tip of Luzon, 18 October 1944. These ships may include: Terukuni Maru, Taiho Maru, Hoten Maru, and Tsingtao Maru.

Japanese merchant ship aground, while under attack by Task Force 38 planes off the north tip of Luzon, 18 October 1944. This ship may be the Taiho Maru.

Footage taken aboard the USS Skate (SS-305). Film shows crew rescuing civilian seaman and operations aboard the vessel. Date unknown.