Japan’s Strategy in Leyte Gulf
By Mike Bennighof, Ph.D.
October 2008

The largest naval battle in human history had its roots in a strategy formed earlier in the century for a potential war with the United States. At the heart of almost every Japanese sakusen, or war plan, for a potential conflict with the Americans lay a decisive fleet battle in friendly waters.

These plans are also the heart of our massive naval wargame, Second World War at Sea: Leyte Gulf. Though the game has over 20 scenarios, including the Battle of the Philippine Sea, the main event is the Battle of Leyte Gulf.

After the Battle of the Marianas in June 1944 (known to the Americans as the Battle of the Philippine Sea), the Imperial General Staff prepared three alternate sakusen, known as “Sho” (“Victory”). Sho-1 mapped the Japanese response to an American landing in the Philippines, Sho-2 that for an attack on Formosa, and Sho-3 a landing in the Ryukyu Islands (the group that includes Okinawa).

Japanese analysis matched American intentions, though given the course of the war to date it wasn’t very hard to guess. American planners chose the Philippines in large part due to Douglas MacArthur’s political desire to redeem “his” promise to liberate the Filipino people. But Formosa had been seriously studied as a potential target as well. Okinawa was seen as an objective for a later stage: The Americans believed they would need it to support an invasion of Japan, while the Japanese thought it might be tempting to their enemies as a base to help interdict traffic between the home islands and the Japanese colonies in Manchuria and Korea. But had the Japanese seriously thought Okinawa at risk, the Sho sakusen probably would have taken a different form.

The three plans shared their basic outline. Japanese naval forces would be kept concentrated at Lingga Roads near Singapore, where they could be more easily fueled with Indonesian oil (some of which is pure enough to burn without refining) or in the Inland Sea in home waters, where they could be better protected from air and submarine attack.

Massive American carrier-based airpower had turned the Battle of the Philippine Sea into what the Americans called the “Great Marianas Turkey Shoot,” and the Japanese knew they could not afford to have their remaining air power frittered away before the decisive battle. The squadrons would be held at bases in the home islands and staged to airfields in the threatened sector when the American moves became clear.

The Japanese believed, probably correctly, that the huge size of the American armada facing them would make it difficult to impossible to hide the target of the invasion. Each variation on the Sho sakusen involved a decoy force to lure the American battle fleet and carrier air power away from the invasion force, while three surface action groups went after the landing beaches.

U.S. Naval Intelligence had picked up on the Japanese strategy of using its carrier force as a decoy, from a tactical manual captured and translated in the summer of 1944 and from a Japanese officer rescued from the torpedoed light cruiser Natori in August 1944. But this information was not widely shared, and few American staff officers on the spot in October 1944 saw the Japanese method for what it was.

Post-war historians, like amateur wargame designers, have judged the Sho sakusen harshly for dividing the Japanese fleet in the face of the enemy, a violation of one of the most basic precepts of military strategy in any culture. But this is probably unfair: The Japanese had to take enormous risks to have even a slim hope of achieving success. No Japanese surface action group was going to defeat what the Americans could place in its path, but by dividing into three segments perhaps one of them could slip past. This depended on two factors. The Americans had to take the bait and chase the Japanese carriers with their own, and the Japanese land-based air forces in the Philippines had to provide effective cover.

American troops started landing on Leyte on 17 October, and the Japanese immediately put Sho-1 into operation. And things began to go wrong from the start.

Vice Admiral Shigeru Fukudome’s Sixth Base Air Force had begun receiving its air complement in early October in preparation for the American assault. But the Japanese had no answer to the American Third Fleet’s 1,200 carrier-based warplanes. They devastated the airfields on Formosa in early October, and as the month progressed did the same to those on Luzon (the main island of the Philippines) and Leyte. Japan’s carefully-gathered air power quickly ceased to exist.

The battleships and cruisers of Vice Admiral Takeo Kurita’s First Strike Force, divided into two sub-groups, would sail around the northern end of Leyte and enter Leyte Gulf through the narrow San Bernardino Strait between Leyte and Samar. Admiral Shoji Nishimura’s Group C would come around Leyte’s southern end, through the Surigao Strait between Leyte and Mindanao. In one of the needless complications so beloved by Japanese planners, a landing force would bring reinforcements to the west shore of Leyte while this naval movement took place.

That last addition may have doomed the Japanese. While Sho-1 orders went out on the 17th, the fleet did not leave Brunei Bay on the north coast of Borneo until 22 October. Kurita’s forces sailed at 0700, and Nishimura’s set out eight hours later. They were to meet in Leyte Gulf on the afternoon of the 25th and destroy whatever American transports remained.

By that time the Americans had already completed their assault landings and the vulnerable troops transports had disgorged their cargo and moved off. Even if successful, the Japanese would have missed their targets.

Despite American preponderance in the air, the Japanese plan almost worked. All of the Japanese forces were spotted, and they suffered through air and submarine attacks along the way. Yet Third Fleet’s Admiral William Halsey took the offered bait and set out on a useless chase after Japanese carriers that had no aircraft. Nishimura ran into the old battleships of Seventh Fleet, while Kurita made it into the gulf. But the battle’s outcome is a tale for another day.

This piece originally appeared in May 2005.

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