Kisarazu Naval Air Group

Kisarazu Naval Air Group was an Imperial Japanese Navy Air Service unit established at Kisarazu Air Field in Chiba Prefecture on 1 April 1936. It was created as the navy’s first land-based bomber group and initially operated six Type 96 Yokosuka B4Y carrier-attack aircraft, supported by two reserve aircraft. Although its designation referred to an air group rather than a commercial brand, the unit functioned as an identifiable military aviation organization with its own personnel, equipment, command structure, base, and operational history. The group entered combat after the outbreak of the Second Sino-Japanese War. Aircraft from the Tateyama and Ōminato air groups were transferred to Kisarazu, increasing its strength to twenty operational bombers and six reserve aircraft. On 15 August 1937, it conducted its first combat mission, attacking Nanjing, then the capital of the Republic of China. It subsequently carried out strategic bombing missions against Shanghai, Hangzhou, and Chongqing, as well as tactical support missions for Imperial Japanese Army advances. Because the Yokosuka B4Y had limited range, the unit operated from forward bases in Shanghai and Nanjing. A temporary fighter element equipped with Type 95 Nakajima A4N aircraft was added in August 1937, but those fighters were withdrawn in October after the navy judged the capability unnecessary for the group’s immediate requirements. Kisarazu was removed from combat operations in January 1940 and returned to its home base. It then served primarily as a training organization, while also conducting patrol duties around the entrance to Tokyo Bay after Japan entered the Pacific War in December 1941. From March 1942, the group transitioned to the Type 1 Mitsubishi G4M bomber, commonly known by the Allied code name Betty. Training on the new aircraft continued through the summer, preparing the unit for deployment to the South Pacific. In August 1942, a nineteen-aircraft detachment was sent to Rabaul on New Britain. There it operated alongside aircraft from the Misawa and Fourth Air Groups during the Guadalcanal campaign. Kisarazu aircraft attacked Henderson Field and other targets on Guadalcanal, and they participated in operations against Allied naval forces. The group shared credit for the sinking of the destroyer USS Colhoun during a bombing operation near Guadalcanal. Repeated missions exposed the unit to intense Allied fighter opposition, combat losses, emergency landings, and aircraft damaged or forced down at sea. The group’s final combat mission took place on 25 October 1942. On 1 November 1942, the surviving organization was redesignated the 707th Naval Air Group. On 1 December 1942, its remaining aircraft and personnel were incorporated into the 705th Naval Air Group. Kisarazu therefore ceased to exist as an independent unit late in 1942. Its historical significance lies in its role as an early Imperial Japanese Navy land-based bomber formation, its participation in the bombing campaign in China, and its later employment during the decisive Guadalcanal air operations.

Kisarazu Naval Air Group was formed on 1 April 1936 at Kisarazu Air Field in Chiba Prefecture. The unit was organized as the first land-based bomber group of the Imperial Japanese Navy Air Service. Its initial equipment consisted of six Type 96 Yokosuka B4Y biplane attack aircraft and two reserve aircraft. The group was subordinate to the Yokosuka Naval District during its first period of service. After the outbreak of the Second Sino-Japanese War, aircraft from the Tateyama and Ōminato air groups were transferred to Kisarazu. This reinforcement raised the unit’s strength to twenty operational bombers and six reserve aircraft. On 15 August 1937, Kisarazu carried out its first bombing mission against Nanjing. It subsequently attacked Shanghai, Hangzhou, and Chongqing, while also providing tactical air support to Imperial Japanese Army operations. The B4Y’s limited range required the group to use forward operating bases in Shanghai and Nanjing. From 27 August 1937, Kisarazu also received Type 95 Nakajima A4N fighters for defense against Chinese aircraft. The fighter element was withdrawn on 10 October because it was not considered necessary for the group’s current operations. Kisarazu remained involved in the China campaign until it was withdrawn on 5 January 1940. It then returned to Kisarazu Air Field and spent much of the following period as a training unit. Following the Japanese attack on Pearl Harbor and the beginning of the Pacific War, the group additionally conducted patrol missions guarding the entrance to Tokyo Bay. In March 1942, it began converting to the Type 1 Mitsubishi G4M bomber. Training with the new aircraft continued until the end of August, when a detachment of nineteen G4M1 aircraft was sent to Rabaul on New Britain. The detachment operated with aircraft from the Misawa Naval Air Group and the Fourth Air Group. The Rabaul-based force entered the Guadalcanal campaign in August 1942. Kisarazu aircraft attacked Henderson Field on 25 August and again on later dates. One aircraft was damaged by United States Marine Corps Grumman F4F fighters during the 26 August mission and was forced to ditch at sea while returning. On 29 August, the group participated in another attack on Henderson Field. During operations against Allied vessels near Guadalcanal, Kisarazu shared credit for sinking USS Colhoun, an American destroyer. On 2 September, nine Kisarazu aircraft and nine aircraft from the Misawa group bombed Henderson Field, causing limited damage without reported losses. Later missions were more costly. On 12 September, two aircraft were lost to Allied aircraft and another made an emergency landing at Buka. A further aircraft was lost over Guadalcanal on 21 September. The group continued attacks on 14, 15, 17, and 21 October, losing another aircraft, and flew its final combat mission on 25 October, during which one more aircraft was lost. The organization was redesignated the 707th Naval Air Group on 1 November 1942. On 1 December, its remaining aircraft and personnel were transferred into the 705th Naval Air Group. Kisarazu therefore ended as an independent unit after roughly six and a half years of service. Its operational record spans the expansion of Japanese naval aviation in China, home-island patrol and training duties, and sustained bomber operations during the Guadalcanal campaign.

• 1942

  Converted to Mitsubishi G4M bombers

  [1]Kisarazu Air Groupen.wikipedia.org

  Kisarazu began re-equipping with Type 1 Mitsubishi G4M bombers in March.

• 1942

  Rabaul deployment

  [1]Kisarazu Air Groupen.wikipedia.org

  A nineteen-aircraft detachment deployed to Rabaul in August for operations in the South Pacific.

• 1942

  Redesignated 707th Naval Air Group

  [1]Kisarazu Air Groupen.wikipedia.org

  The original Kisarazu designation was replaced by the 707th Naval Air Group on 1 November.

• 1942

  Absorbed into 705th Naval Air Group

  [1]Kisarazu Air Groupen.wikipedia.org

  The remaining aircraft and personnel were incorporated into the 705th Naval Air Group on 1 December.

• 1940

  Withdrawn from China combat operations

  [1]Kisarazu Air Groupen.wikipedia.org

  The group ended its combat deployment in China and returned to Kisarazu for training duties.

• 1937

  First combat mission over Nanjing

  [1]Kisarazu Air Groupen.wikipedia.org

  Kisarazu conducted its first recorded combat bombing mission against Nanjing on 15 August.

• 1936

  Kisarazu Air Group formed

  [1]Kisarazu Air Groupen.wikipedia.org

  The Imperial Japanese Navy established the group at Kisarazu Air Field as its first land-based bomber group.

A pioneering Imperial Japanese Navy land-based bomber group, combining airbase defense, pilot and crew training, strategic bombing, tactical support, and forward operations in the Pacific War.

• Naval attack aircraft

  Type 96 Yokosuka B4Y

  The B4Y was Kisarazu’s initial bomber and attack aircraft. The biplane’s limited range shaped the group’s China operations, requiring forward deployment from bases in Shanghai and Nanjing.

• Fighter aircraft

  Type 95 Nakajima A4N

  A4N fighters were temporarily assigned from August to October 1937 to provide protection against Chinese fighters. The fighter element was withdrawn after a short period because the group did not require it for its prevailing mission profile.

• Land-based bomber · 1942

  Type 1 Mitsubishi G4M

  The Mitsubishi G4M became Kisarazu’s principal aircraft during its final operational period. After conversion in 1942, G4M1 bombers operated from Rabaul against Henderson Field, Guadalcanal, and nearby Allied naval targets.

• 1942Guadalcanal campaign

  Solomon Islands · South Pacific

  A Kisarazu detachment based at Rabaul carried out repeated bomber missions against Henderson Field and other Guadalcanal targets, while also participating in attacks on Allied shipping.

  Outcome. The group suffered aircraft losses and flew its final combat mission on 25 October 1942.

  Source
• 1937Second Sino-Japanese War bombing campaign

  China

  Kisarazu bombed Nanjing, Shanghai, Hangzhou, and Chongqing, and conducted tactical missions in support of Japanese Army advances. Forward bases were used because of the limited range of its B4Y aircraft.

  Outcome. The group remained in China until its combat withdrawal in January 1940.

  Source

• 1942

  Conversion to Mitsubishi G4M bombersGeneration change

  Background

  The unit required a more capable land-based bomber for Pacific operations after Japan entered the war with the United States and its allies.

  Action taken

  Beginning in March, Kisarazu replaced its earlier equipment with Type 1 Mitsubishi G4M bombers and trained through August.

  Aftermath

  The conversion allowed the group to deploy to Rabaul and participate in long-range operations around Guadalcanal.

  Source

• 1942

  Redesignation and incorporationOther

  Background

  Following its 1942 combat deployment, the Imperial Japanese Navy reorganized its air-group structure.

  Action taken

  Kisarazu was redesignated the 707th Naval Air Group on 1 November and incorporated into the 705th Naval Air Group on 1 December.

  Aftermath

  The Kisarazu organization ceased to operate as an independent naval air group.

  Source

• 1937

  Forward deployment for China operationsStrategy

  Background

  The B4Y’s range was insufficient for all missions from Kisarazu, while the group was being used against targets in China.

  Action taken

  The group operated from forward bases in Shanghai and Nanjing.

  Aftermath

  Forward basing enabled bombing operations against targets that could not reliably be reached from Japan.

  Source

• 1942

  Kisarazu detachment deploys to Rabaul[1]Kisarazu Air Groupen.wikipedia.org

  Other

  A nineteen-aircraft detachment reached Rabaul and joined other Japanese naval air formations for operations in the Guadalcanal campaign.

• 1942

  Kisarazu participates in Guadalcanal bombing operations[1]Kisarazu Air Groupen.wikipedia.org

  Other

  The group repeatedly attacked Henderson Field and other targets around Guadalcanal, suffering aircraft losses to Allied fighters and operational accidents.

• 1942

  Kisarazu Air Group redesignated as the 707th Naval Air Group[1]Kisarazu Air Groupen.wikipedia.org

  Other

  The surviving unit was redesignated on 1 November, ending Kisarazu’s existence under its original designation.

• 1937

  Kisarazu begins bombing operations against Nanjing[1]Kisarazu Air Groupen.wikipedia.org

  Other

  The group conducted its first combat mission against Nanjing during the Second Sino-Japanese War and later operated against several Chinese cities.

• 1936

  Kisarazu Naval Air Group established at Kisarazu Air Field[1]Kisarazu Air Groupen.wikipedia.org

  Other

  The Imperial Japanese Navy established Kisarazu as its first land-based bomber group, initially equipping it with Yokosuka B4Y aircraft.

1. 1Kisarazu Air Groupen.wikipedia.org