Genzan Kōkūtai (Genzan Air Group)
Imperial Japanese Navy (IJN)

Background
The Genzan Kōkūtai (Genzan Air Group) was a land based unit of the Imperial Japanese Navy (IJN) that operated the Type 96 Land Based Attack Bomber (Rikko) / G3M2 Nell. Abbreviated as Genzan Ku. In English, spelled Genzan Kokutai. On November 1, 1942 the Genzan Kokutai fighter unit was redesignated as the 252 Kōkūtai (252 Ku) and the Genzan Kokutai bomber unit was redesignated 755 Kōkūtai (755 Air Group).

Wartime History
On November 15, 1940 formed as the Genzan Kōkūtai (Genzan Air Group) 元山海軍航空隊 in Genzan (Wonsan) in Korea. At the start of the Pacific War, deployed to Saigon in French Indochina.

On December 9, 1941 nine G3Ms from the Genzan Kōkūtai attack Kuantan from an altitude of 5,000'. They were intercepted by RAAF Hudson A16-17 piloted by F/O Widmer from No. 8 Squadron who was returning from a mission, and the pilot was credited with a G3M2 Nell probable over Kuantan (an observer on the ground reported seeing a plane on fire and two parachutes deployed). On December 31, 1941 he was a navigator on a PBY Catalina from No. 205 Squadron.

On December 10, 1941 G3M Nells participated in the sinking of the HMS Prince of Wales (53) and HMS Repulse (34). Lost to anti-aircraft fire was one bomber and its crew.

On January 22, 1942 G3M Nells bombed Kallang Airport on Singapore. Afterwards, provided air support for Japanese offensives in Malaya including the landings at Endau.

On February 15, 1942 during the Gaspar Strait Sortie, 23 G3M Nells bomb Allied warships from high altitude without causing any damage.

At the end of February 1942, moved to Bangkok and assigned to patrols over the Indian Ocean. Facilities at Bangkok were not satisfactory and the unit was soon reassigned to Palembang Airfield on Sumatra, with some aircraft dispersed to Kuching in Sarawak.

On May 1 1942, Genzan was based at Vunakanau Airfield near Rabaul and bombs Port Moresby and participated in the Battle of the Coral Sea.

On May 18, 1942 eighteen G4M2 Nells from Genzan Kokutai led by Lt. Rokuo Nikaido took off from Vunakanau Airfield armed with 60kg bombs on a mission against 12 Mile Drome (Berry) hitting the runway, damaging huts and destroying two parked Airacobras and damaging another Airacobra.

On May 24, 1942 in the morning, B-26 Marauders from the 22nd Bombardment Group (22nd BG) bomb at Vunakanau Airfield and destroy the Genzan Kokutai headquarters building and heavily damage a G4M1 Betty and bomb fragments damage three other G4M1 Bettys.

On June 1, 1942 At 7:45am nineteen G3M2 Nells from the Genzan Kokutai led by Lt. Ishihara took off from Vunakanau Airfield on a bombing mission against Port Moresby. At 8:30am twelve A6M2 Zeros from the Tainan Kokutai took off from Lakunai Airfield led by Lt. Kawai Shiro to escort the bombers but shortly afterwards three Zeros aborted the mission due to mechanical issues. This left nine Zeros to provide top cover for the bombers. At 10:00am another twelve Zeros took off from Lae Airfield as additional escorts. At roughly 10:45am over Cape Ward Hunt, the bombers and the 21 escorting Zeros formed up but were observed by Australian spotters and reported to Port Moresby. Before crossing the Owen Stanley Range, one bomber experienced engine trouble and instead patrolled the north coast, released its bomb load south of Buna and returned. At 11:40am the Japanese formation arrived over Port Moresby and the Zeros intercepted 10-15 fighters while the Nells bombed from 20,000' targeting the wharf and Coast Famer anchored in Fairfax Harbor. Intercepted by P-39 Airacobras, A6M2 Zero pilot WO Miyazaki Gitaro was shot down near 30 Mile Drome (Rorona). One G3M2 Nell was damaged with three crew wounded and diverted to land at Lae Airfield.

During July 1942, after the cancellation of Operation MO, the unit was withdrawn to Japan and was based at Misawa Airfield for training.

On September 20, 1942 the Genzan Kokutai figher butai of 36 A6M Zeros was expanded to 60 Zeros.

On November 1, 1942 the Imperial Japanese Navy (IJN) renamed air groups with three digit identifiers. The Genzan Kokutai fighter unit was redesignated as the 252 Kōkūtai (252 Ku). The Genzan Kokutai bomber unit was redesignated 755 Kōkūtai (755 Air Group).

Tail Codes
The group used different codes at various dates with three digit aircraft codes for each aircraft.

カ-??? (fighter tail code) - 1940
G-??? (bomber tail code) – 1940-1942

Aircraft
G3M2 Nell crashed near Penang
G3M2 Nell 460 Tail G-315 abandoned Lae Airfield.
G3M2 Nell 462 Tail G-375 destroyed at Lae Airfield.

References
Kodochosho Genzan Kōkūtai

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