Aircraft History
Built by Mitsubishi at Nagoya No. 3 Works. Delivered to the Imperial Japanese Navy (IJN) as G4M1 Model 11 Type 1 Attack Bomber manufacture number unknown. This aircraft was painted with green upper surfaces and gray lower surfaces. Assigned to the 705 Kōkūtai. Tail code T1-326, later changed to 326.

Wartime History
Assigned to the 705 Kōkūtai with tail code T1-323, later changed to 323. Departed Japan flying southward via Truk before arriving at Vunakanau Airfield near Rabaul.

This bomber was painted with standard green upper surfaces and gray lower surfaces. The upper nose and each upper engine cowling was planted black. The leading edge of the inner wings had a yellow identification stripe. The fuselage Hinomaru was outlined with a white square. Tail code 326 was painted in white on both sides of the tail.

"Yamamoto Mission"
During Operation I-Go, Admiral Isoroku Yamamoto, Commander in Chief of the Combined Japanese Fleet and his senior staff planned an inspection tour of forward airfields and bases in the Shortlands and southern Bougainville. The purpose of this visit was to boost moral after the Japanese losses on Guadalcanal and thank the Japanese Army for cooperation.

Knowledge of his flight was gleamed from a coded Japanese message sent on April 13, 1943 which American intelligence intercepted and had broken their Naval code. Decoded, the message outlined Yamamoto's itinerary and timetable. According to the intercept, Yamamoto would depart "RR" Rabaul at 0600 in a medium attack plane [G4M1 Betty] and land at "RXZ" Ballale Airfield at 0800. Then, proceed by subchaser to "RXE" Shortland at 0840, then depart at 0945 aboard the same subchaser and return to Ballale at 1030, then depart at 1100 aboard G4M1 Betty and arrive at Buin Airfield (Kahili) at 1110. Finally at 1400 depart "RXP" Buin Airfield (Kahili) by G4M1 Betty and arrive back at Rabaul at 1540. All the times were in the Tokyo timezone used by the Imperial Japanese Navy.

A secret plan was made to to intercept and shoot down the bombers. Eighteen P-38 Lightings from the 347th Fighter Group and 18th Fighter Group would fly 435 miles over the open sea, the longest intercept mission by land based aircraft during World War II.

Mission History
On April 18, 1943 before dawn took off from Vunakanau Airfield near Rabaul under the command of FPO2/c Hiroshi Hayashi with G4M1 Betty 2656 Tail 323. Both bombers flew eastward then landed at Lakunai Airfield to pick up the high ranking passengers. Five passengers boarded this aircraft including Vice-Admiral Matome Ugaki, Captain Motoharu Kitamura, Rinji Tomoro, Kaoru Imananka and Suteji Muroi plus their baggage.

At 6:10am both bombers took off from Lakunai Airfield escorted by six A6M Zeros of the 204 Kōkūtai and the formation departed on schedule and proceeded as planned southeast and was scheduled to land at 8:00am at Ballale Airfield. The weather was described as fine with intermittent cumulus clouds.

Meanwhile, P-38 Lightnings of the 339th Fighter Squadron took off from Fighter 2 (Kukum) on Guadalcanal as part of Operation Peacock the top secret "Yamamoto Mission" to intercept and shoot down the Admiral's bomber. Each P-38 had two auxiliary fuel tanks for a six hundred mile round trip flight.

South of Empress Augusta Bay on Bougainville, they spotted the Japanese formation and the P-38s split up to engage the escorting A6M2 Zeros while the attack group engaged the bombers. Roughly a mile away, the P-38s were spotted by the Japanese formation, G4M1 Betty 2656 Tail 323 with passenger Admiral Isoroku Yamamoto dove to low altitude as a defensive maneuver and was followed by this Betty.

After the shoot down of G4M1 Betty 2656 Tail 323, this bomber was targeted by P-38G #100 piloted by Holmes, P-38G piloted by Hine and P-38G "Miss Virginia" 43-2204 #147 piloted by Barber. During the attack, Holmes dove at the bomber and opened fire causing the left engine to smoke. Next, attacked by Hine. Finally, Barber fired into the fuselage and claimed to cause it to explode.

In fact, this Betty was damaged but sucessfully ditched into the sea off Moila Point on southern Bougainville. Three survived and swam ashore including Vice-Admiral Matome Ugaki, Captain Motoharu Kitamura and Hiroshi Hayashi. The rest were killed in the air or died in the ditching. Later, the body of one of the crew washed ashore.

Fates of the Crew
Ashore, the three survivors were spotted by friendly forces and were taken to nearby Kahili (Buin).

Vice-Admiral Matome Ugaki was transported back to Japan and convalesced to recover from his injuries and blamed himself for Yamamoto's death. On August 15, 1945 after the Emperor made the radio annoucement that Japan would surrender, Ugaki noted in his personal diary that he had not yet received an official cease-fire order, and that as he alone was to blame for the failure of his aviators to stop the enemy and decided to fly a final mission himself to show the true spirit of bushido. His subordinates protested but he insisted, posed for pictures, removed his rank insignia and wore a Type 3 uniform (dark green) and carried a sword given to him by Admiral Yamamoto then boarded a D4Y Judy piloted by Warrant Officer Akiyoshi Endo. During the flight, Endo sent Ugaki's final radio message at 7:24pm reporting that the plane had begun its dive onto an American vessel, but was instead shot down by anti-aircraft fire or crashed into the sea.

Pilot Hiroshi Hayashi survived the Pacific War. As of 2005, he was still alive and lived in retirement on Yaku Sihima Island. Postwar, he declines interviews from Japanese researchers and authors about his wartime service or related to the events of this mission.

Wreckage
This Betty ditched into the seas roughly 100m off Moila Point on southern Bougainville. After the crash, the Japanese searched for the wreckage but only found small pieces in the area.

During April 2018, a team from Pacific Wrecks including Rod Pearce aboard MV Barbarina attempted to search for this Betty using side scan sonar to survey the presumed ditching area, but were unable to locate the wreckage. Possibly, the wreckage of this Betty was covered by sand over the decades or disappeared.

References
Kodochosho, 705 Kōkūtai, April 18, 1943
13th Fighter Command "Fighter Interception Report" April 18, 1943
Fading Victory The Diary of Admiral Matome Ugaki, 1941-1945 page 222-223, 330-331, 350-360 plus footnotes
13th Fighter Command in World War II chapter 8 Yamamoto Mission by Jim Lansdale pages 137 -162
Bureau of Aircraft Accidents Archives - Crash of Mitsubishi G4M off Moila Point "MSN: 2659 ?"

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Last Updated
September 27, 2019