Operation Cartwheel

The Japanese

The I Operation:
March-April 1943

by James Miller, jr.

While Japanese Army troops were busy building roads in New Guinea, the Japanese Navy had also taken a hand in an effort to beat the Allies. Galled by the admittedly crushing defeat in the Bismarck Sea, fully aware of the threat that Allied air activity in the South Pacific presented to their shipments of troops and supplies to New Georgia and Santa Isabel, and concerned over their declining air strength, the Japanese decided to gather more planes, smash Allied air power, and attack Allied shipping in the Southeast Area.

Japanese air strength was somewhat less than substantial at this time. In March 1943 there were only about three hundred planes--one hundred Army and two hundred Navy--in the Southeast Area. Rabaul frequently complained that Tokyo never sent enough replacements to replace losses. Toward the end of March General Imamura asked Imperial Headquarters for more. Headquarters did send more, but not enough, to satisfy Imamura, and some planes that were dispatched never arrived. For example, the 68th Air Regiment navigated so badly while flying from Truk to Rabaul that many of its planes failed to find Rabaul and were lost at sea.

Admiral Isoroku Yamamoto, Commander in Chief of the Combined Fleet, decided to take a hand in the attempt to beat the Allies out of the air. For this effort, given the code name I Operation, he sent the planes from the 3d Fleet carriers at Truk to join with iith Air Fleet planes at Rabaul, Kavieng, Buin, Buka, and Ballale. He took headquarters of both the Combined and 3d Fleets from Truk to Rabaul to direct the I Operation, which involved more than three hundred aircraft.

Japanese aircraft had concentrated against the Allied New Guinea bases in March, and the month had been a quiet one on Guadalcanal. But that the Japanese had renewed their interest in the Solomons was demonstrated to the Allies on 1 April when bombers and fighters struck at the Russells. Air combats raged for three hours as Allied fighters beat off the attackers, losing six of their number in the process. (Craven and Cate, The Pacific: Guadalcanal to Saipan, p. 212.)

Main Phase

Six days later, 7 April, came the main phase of I Operation in the Solomons. It was a splendid opportunity for the Japanese, for there were many targets around Guadalcanal. A naval task force, having fueled at Tulagi, was steaming northwest en route to shell Vila and Munda that night. Including cargo ships, transports, and the task force, there were present about forty ships of corvette size or larger, and a larger number of smaller vessels. In addition much ammunition, fuel, and equipment were being stored on Guadalcanal in preparation for the invasion of New Georgia.

To attack these lucrative targets, Yamamoto dispatched 117 fighters and 71 bombers. Coastwatchers on New Georgia, counting more than 160 planes overhead, flashed warnings southward. Halsey canceled the scheduled bombardment; the task force rounded Florida and sped down Indispensable Strait. Other ships and craft started getting under way and most had reached open water when the Japanese arrived about 1500.

While Allied bombers flew to the southeast to avoid the Japanese, all available Allied fighters, seventy-six in number, took the air to intercept. P-38's (Lightnings) flew on top, and beneath them, at various altitudes, were F4U's (Corsairs), F6F's (Hellcats), and P-39's (Airacobras).

As the Japanese planes broke up into separate flights, a general melee ensued. The skies above the Russells, Tulagi, and the waters between Guadalcanal and Florida saw violent combat. According to the Japanese, "resistance offered by the ten or so enemy Grummans [F6F's] and P-38's was beaten down and the attack on shipping was carried out." They reported seriously damaging most of the Allied ships, a claim that is as inaccurate as their statement that only ten Allied fighters tried to intercept. (Southeast Area Naval Operations, II, Japanese Monogr No. 49 (OCMH), 13.)

They sank the New Zealand corvette Moa, the U.S. oiler Kanawha, and the U.S. destroyer Aaron Ward, and damaged one other oiler. They apparently never sighted the task force. Seven Allied fighters and one pilot were lost, but the Japanese lost many more. (Craven and Cate, The Pacific: Guadalcanal to Saipan, pp. 212-13; Morison, Breaking the Bismarcks Barrier' pp. 120-24. Allied airmen claimed thirty-nine Japanese planes downed in air combat, while surface ships claimed twenty-five. There were undoubtedly many duplications. The Japanese admit losing twenty-one.)

Yamamoto, apparently satisfied with the performance over Guadalcanal, then turned against the Allies in New Guinea. On 11 April, 22 bombers and 72 fighters struck at Oro Bay. They sank one merchant ship, damaged another so badly that it had to be beached, and hit an Australian minesweeper. Next day 131 fighters and 43 bombers flew over the Owen Stanleys to hit Port Moresby. There were few Allied fighters on hand to oppose them. As he himself points out, General Kenney had expected the attack to hit Milne Bay and had sent most of his fighter strength there. (Kenney, General Kenney Reports, pp. 225, 22829.)

Fortunately the damage was very light. Two days later the Japanese fulfilled Kenney's expectations by attacking Milne Bay, but they did little damage. One Dutch merchant ship was a total loss, and a British motorship and another Dutch ship were damaged. Yamamoto then concluded the I Operation, which he regarded as highly successful, and returned the carrier planes to their parent units at Truk. The Japanese, apparently misled by optimistic pilots' reports, boast of destroying 1 cruiser, 2 destroyers, 25 transports, and 134 planes, while losing 42 planes themselves. But actual Allied losses in the Solomons and New Guinea were 1 destroyer, 1 tanker, 1 corvette, 2 Dutch merchant ships, and about 25 planes.

Ambush Over Kahili

Yamamoto then decided to pay a morale-building visit to the Buin area. He, his chief of staff, and other officers left Rabaul on 18 April in two twin-engine bombers escorted by fighters. When the party reached a point thirty-five miles northwest of Kahili, the airdrome near Buin, they were jumped by eighteen P-38's from the South Pacific's Thirteenth Air Force, which had been sent there for that very purpose.

When Admiral Halsey returned to Noumea after conferring with MacArthur in Brisbane, he learned that American intelligence officers had discovered the exact time on 18 April Yamamoto was due to reach the Buin area from Rabaul. Admiral Nimitz and his staff agreed that disposing of Yamamoto would advance the Allied cause, so the Commander, Aircraft, Solomons, was told to shoot him down. The eighteen P-38's, manned by picked pilots and led by Maj. John W. Mitchell, were sent on the mission. Taking off from Henderson Field on Guadalcanal, they flew low over the waves for 435 miles by a circuitous route to the interception point northwest of Kahili. Yamamoto's flight hove in sight just as its fighter escort was leaving. Mitchell's attack section, led by Capt. Thomas G. Lanphier, Jr., bored in and Lanphier made the kill. Yamamoto's plane crashed in the Bougainville jungle. He died. The other plane fell in the sea, but the chief of staff, whom it was carrying, survived. One American pilot was lost. This Lucifer-like descent of the aggressive, skillful Yamamoto, perhaps the brightest star in the Japanese military firmament, was a severe blow to the morale of the Japanese armed forces. (Craven and Cate, The Pacific: Guadalcanal to Saipan, pp. 213-14; Halsey and Bryan, Admiral Halsey's Story, pp. 155-57; Morison, Breaking the Bismarcks Barrier, pp. 128-29. There are some differences in these accounts, chiefly regarding Yamamoto's destination and time of arrival. Halsey and Bryan, and Craven and Cate say he was to arrive at Ballale at 0945. Morison says he was due at Kahili at 1145.)

The Big Raid

By early June, the Allies in the Solomons realized that the Japanese were again determined to accomplish what the I Operation had failed to do-cut the lines of communication to Guadalcanal by air action. Yamamoto fell from the skies believing that he had succeeded, but by June the enemy leaders at Rabaul knew that the Allies were freely building up supplies on Guadalcanal.

On 7 June the Japanese inaugurated another series of fighter-escorted bombing attacks against Guadalcanal. Planes from the Russells made the first interception that day. According to Allied accounts, the Japanese lost twenty-three fighters, four of them to P-40's of the No. 15 Royal New Zealand Air Force Fighter Squadron in its Solomons debut. Nine Allied planes were shot down but all pilots were recovered. In a second attack five days later, the Japanese are reported to have lost thirty-one planes, the Allies, six.

By mid-June Allied reconnaissance planes were reporting 245 planes at Rabaul, with the forward fields in the northern Solomons filled to capacity. What some Allied veterans of this period call "the big raid" on Guadalcanal came on 16 June when a large force of enemy bombers and fighters, numbering over 100 planes, flew down to attack Guadalcanal. (USSBS, The Allied Campaign Against Rabaul, P. 46, says 150-60 planes attacked on 6 June, but 16 June is apparently intended.)

The coastwatchers again had sent their timely warnings, and 104 Allied fighters were ready. As in April, they intercepted promptly, the Japanese formations broke up into smaller flights, and air combats raged. Whenever possible ship- and shore-based antiaircraft took the enemy under fire. The Japanese hit three Allied ships, two of which had to be beached, and did some damage to shore installations before they were driven off. Six Allied fighters were shot down. The number of enemy planes destroyed was large, although the exact total cannot be determined. The Allies claimed 98. One Japanese account admits the loss of about 30 planes. (Craven and Cate, The Pacific: Guadalcanal to Saipan, pp. 218-ig; U.S. Strategic Bombing Survey, The Thirteenth Air Force in the War Against Japan (Washington, 1946); Southeast Area Naval Operations, III, Japanese Monogr No. 50 (OCMH), 53.)

Neither the I Operation nor "the big raid" achieved substantial results. The Japanese failed, partly because their efforts were brief and sporadic rather than long and sustained, and partly because Allied resistance had been vigorous and generally skillful.

More The Japanese

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