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UNHINGING THE JAPANESE GRAND STRATEGY

Captain Ruhe is Editor Emeritus of THE SUBMARINE REVIEW and is the author of War in the boats, Washington/London, Brassey’s Inc., 1994.

This year marks the 50th anniversary of the conclusion of the war with the Japanese. It is thus useful to recall why the Japanese expected to win the Pacific War against the United States.

In effect, the Japanese had a Grand Strategy which they felt would produce a victory over a country that had gone soft and hence in a year or two would lose its resolve to continue fighting a really tough war. The Japanese Grand Strategy was predicated on a successful surprise attack on U.S. fleet units in Pearl Harbor to reduce the U.S. potential for contesting control of Pacific waters. Invasion of Southeast Asia countries followed, providing a source of raw materials for fueling the Japanese war-making machine. Then inner and outer defense perimeters of Pacific islands were heavily fortified to protect both the flow of war supplies from the conquered countries and Japan itself. It was assumed that breaching these island defense perimeters would be so costly to the U.S. in men and equipment that the U.S. would let the war wind down while accepting a fait accompli of the Japanese conquests. The victory was not planned by the Japanese, only a cessation of hostilities followed by an uneasy peace for perhaps a long time.

This Japanese strategy for victory seemed plausible, except that the Japanese miscalculated the toughness of their enemy. (‘The Japanese certainly misguessed as to the tenacity of U.S. submariners in remaining on the offensive despite all-out efforts to destroy them.) Also, the Japanese failure to take eastern New Guinea, their failure to close the gap in their outer defense perimeter at Midway, and their allowing the U.S. to gain a toehold in the eastern Solomons at Guadalcanal-along with their failure to adequately resupply their war economy-proved to be the undoing of their Grand Strategy for winning the Pacific war. The planned invasion of the northeast coast of Australia was also put on hold with the buildup of MacArthur’s forces in northeast Australia and at Port Moresby, establishing the inevitability of MacArthur’s forces retaking the Philippines.

This offbeat version of the war in the Pacific is derived from the observations I made as a submariner on eight war patrols, three from Brisbane, Australia and five from the West Australian ports of Darwin and Fremantle and as recorded in my book War in the Boats. Of course, this view of history is colored by the rose-tinted glasses with which, as a true believer in the great value of submarines, I saw their efficacy in a sea war.

My three war patrols in 1942 up into the Solomon Islands area typified the impact of U.S. submarines on the unhinging of the Japanese Grand Strategy. The first two in the S 37 and the third in the fleet boat SEADRAGON tell the story of the stop-gap effort to prevent an invasion of the northeast coast of Australia and the breaching of the Japanese outer defense perimeter at Guadalcanal. The enemy’s paranoic fear of U.S. submarines generated by a few of these old crock boats, with their occasional torpedoing of valuable Japanese merchant ships and warships, seemingly had a decisive effect on Japanese operations for consolidating the elements of their Grand Strategy.

Starting in April 1942 with the arrival at Brisbane of five S boats from Panama and five from the Asiatic fleet, these antiquated, slow, 900 ton submarines of 30 days patrol endurance, a crew of 42 men and armed with Mk 10 torpedoes with only 360-pound warheads, produced results far greater than could be expected. At least the few torpedoes fired by the S boats actually exploded and were quite devastating, unlike the new Mk 14s used by the newer fleet boats, which were premature or were duds only too frequently.

In early May, two days after the Coral Sea Battle, the S 42 sank the large minelayer OKINOSHIMA that was loaded with troops and headed from Rabaul to Buna on the north coast of eastern New Guinea. On the next day, the S 44 sank the repair ship KEUO in about the same location. Both sinkings were of considerable importance in ensuring MacArthur’s holding position at Port Moresby key element in his I shall return strategy for retaking the Philippines. In June the S 44 sank a Japanese supply ship close to Guadalcanal and on 8 July the S 37 sank a naval auxiliary troop transport off Rabaul.

These sinkings seemed to generate a flurry of Japanese activity to strengthen their forces on Guadalcanal. It had become apparent that with the buildup of MacArthur’s Army forces in northeast Australia it was imperative for the Japanese to use their hastily constructed airfield on the eastern end of Guadalcanal for the interdiction by long-range aircraft of MacArthur’s sea supply lines from the U.S. to Australia. Thus when, on 7 August \942, 12,000 U.S. Marines were landed on Guadalcanal to seize the airfield there, the Japanese immediately responded by sailing a six-ship convoy of transports heavily loaded with troops and their battle equipment from Rabaul to throw the Marines off Guadalcanal. But a single torpedo fired by the S 38 sank a transport. A decisive blow. The Convoy Commander, fearing further sinkings as he proceeded down the Slot turned bis remaining five ships back to Rabaul, giving the U.S. Marines a chance to consolidate their hold on Henderson Field and begin the breaching of the Japanese outer defense perimeter.

Two days later, on 10 August, when it seemed that a large force of Japanese heavy and light cruisers had won their finest naval victory of the Pacific War in the Night Battle off Savo Island-sinking four heavy cruisers of the Allies and seriously damaging a fifth with little damage to any of the Japanese warships-the Commander of the Japanese forces nevertheless turned his forces back to their home base at Kavieng. They might have sailed another 20 miles to the east and decimated the many U.S. ships that were offloading at Lunga Roads off Henderson Field. But inexplicably, in the moment of victory, the Japanese let the U.S. ships off the hook. Was it fear of submarines that affected the Commander’s actions? Possibly.

Ironically the S 44 sank the heavy cruiser KAKO just short of Kavieng giving license to the paranoia the Japanese had about U.S. submarines. Subsequently, the S 41 damaged two supply ships near Rabaul, the S 37 put a torpedo into a big warship near Savo Island, the S 44 and S 42 damaged destroyers near Guadalcanal and the S 47 put two torpedoes into a heavy cruiser that was attempting to bombard Henderson Field.

By November, when I arrived in the fleet boat SEADRAGON in St. George’s Channel off Rabaul, the ubiquitous U.S. submarines were believed to be everywhere and anywhere in the Solomons area, causing the Japanese to do a lot of dumb, inefficient things. Large numbers of depth charges were dropped on false contacts. Periscopes were seen everywhere and evasive action was taken needlessly. Single ships were escorted by several of the best Japanese fleet destroyers and they turned back if even a suspected submarine was in their path. Reinforcement of their beleaguered troops in New Guinea and the Solomons was carried out by many inefficiently loaded, high speed 45-knot fleet destroyers that zigzagged widely and randomly dropped depth charges if they felt they were crossing over a lurking submarine. The Japanese also wasted their best submarines in an unprofitable pursuit of antisubmarine warfare.

It was the persistency of attacks by our boats, even though torpedoings of Japanese ships were infrequent, that produced an incomprehensible X-factor in Japanese planning that muddied their thinking and unhinged their Grand Strategy for winning the Pacific war.

Ensuring that the U.S. would win, however, was due in great part to the successful shipping attrition war that was fought in the South China Sea by the boats out of West Australian ports. Though these submarines suffered initially from faulty torpedo performance that diluted their potential for sinking ships, they subsequently sank many important ships carrying raw materials from the Japanese Southeast Asia conquests to the Empire’s war-making machine. (The CREV ALLE, on which I made five war patrols from Fremantle, typified the problems and successes of the fleet boats firing Mk 14 torpedoes, in eventually bringing. Japan to her knees in her attempts to stop the U.S. forces from moving to the shores of Japan.) So successful, for example. was the submarine campaign in sending high priority oil tankers to the bottom that when the Japanese fleet was ordered to congregate for the defense of the Philippines, the Commander of the major fleet units at Truk called for all available oil tankers to be diverted for his fleet’s use or his units could not take part in what came to be the Battle of Leyte Gulf. Later in 1945 when the Japanese fleet was to be used for one last major fleet action off Okinawa, the force of ships centered around the super-battleship YAMATO sallied forth from the Inland Sea with only enough fuel on board for two days of fighting-and then total fuel exhaustion.

Submarines. it should be recognized, played a major role in making a U.S. victory possible just as it had been partially but importantly instrumental in denying victory to the Japanese.

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