Nakajima J1N "Gekko" (Irving), 153 Kokutai

A set of photos feature Nakajima J1N "Gekko" (Irving) flown by the 153 Kokutai as indicated by the numbers "153-" and "53-" on the aircraft tails.

A late-model Nakajima J1N "Gekko" (Irving) Model 11 (J1N1-S) with the step on the dorsal fuselage removed. This particular aircraft has had its downward-facing guns removed.

The same Nakajima J1N "Gekko" (Irving) Model 11 (J1N1-S) seen in the previous photo. On January 5, 1945, this "Gekko" of the 153rd Kokutai, Sento 851 Hikotai, made an emergency landing at Taisho Army Airfield in Osaka due to engine trouble. The drop tanks under the wings were the same type as those used on the Zero fighter (300 liters capacity) and were painted light gray. The crew, consisting of Chief Petty Officer Takano and LTJG Hayashi, and others received eight aircraft, including this one, at Atsugi Air Base. Two of the aircraft, including Hayashi's, landed at Taisho on their way to Kanoya. They departed the following day, the 6th, and headed to Taiwan via Kanoya to rendezvous with the main force. Because all the aircraft stationed at Clark Air Base in the Philippines, where they were scheduled to deploy, had been withdrawn, the 851 remained in Taiwan.

A Nakajima J1N1-Sa "Gekko" (Irving) captured by US forces at Clark Air Base. The inspection/maintenance hatch is open, and the hole through which the barrel of the Type 99 Model 2 cannon protrudes is clearly visible. The photograph was taken on February 12, 1945, one month after the defeat in the air battles over the Philippines. It is believed to be an aircraft of Sento 812 Hikotai, the last "Gekko" unit to advance under the command of the 153rd Kokutai.

The same Nakajima J1N1-Sa "Gekko" (Irving) captured by US forces at Clark Air Base.

Sometimes the aircraft in this photo is identified in various sites and FB pages as a Kawasaki Ki-45 "Toryu" (Nick).  

One more photo of the same Nakajima J1N1-Sa "Gekko" (Irving) captured by US forces at Clark Air Base. 

Artwork by Kuroki Hitomi, of the previously seen Nakajima J1N1-Sa "Gekko" (Irving) captured by US forces at Clark Air Base, featured in FAOW #57. 

Below is a set of photos featuring another 153 Kokutai "Gekko", tail code "153-71" captured by US forces at Clark Air Base. 

Note the "H-6" (officially the Type 3 Airborne Radio No. 6) radar antennae protruding from the fuselage sides. The H-6 was the most widely deployed radar for Japanese Navy aircraft, seeing extensive use in maritime search and patrol missions from 1944 onwards. It operated on a wavelength of 2 meters (150 MHz); specifications indicated a detection range of 95 km for large ships and 55 km for a single large aircraft.

Approximately 2,000 units of the H-6—which utilized a maximum-sensitivity detection method—were manufactured by Japan Radio Co. and Kawanishi.

Unit history from the Japanese Wikipedia:

As land battles in New Guinea intensified and a counteroffensive by the U.S. Army—which had been rebuilding its forces in Australia—loomed, there arose a need for long-range reconnaissance units operating on the front lines stretching from western New Guinea to eastern Dutch East Indies. The 753rd Kokutai, which had long been based at the Kendari airfield on Celebes Island and was responsible for bombing missions toward the strategic stronghold of Darwin, had also been performing long-range reconnaissance duties; however, it was being severely depleted without ever being able to return to the home islands. Consequently, the 153rd Kokutai was formed as a new unit dedicated exclusively to reconnaissance. However, initially, they were unable to procure reconnaissance aircraft. Consequently, even though they had a full complement of personnel, they could not conduct reconnaissance missions and could do little more than analyze and relay reconnaissance information obtained from Army air units. 

January 1, 1944: Established at Kendari Airfield with Hsinchu Airfield as its home base (authorized strength: 12 land-based reconnaissance aircraft; however, no aircraft were available initially).

Directly under the command of the Southwest Area Fleet and the 13th Air Fleet.

By March, reconnaissance operations began using Mitsubishi Ki-46 "Dinah" transferred from the Army. In early March, Yokosuka D4Y "Suisei" (Judy) arrived from the mainland.

March 5, 1944: Reconnaissance of southern New Guinea conducted with two "Suisei".

March 10, 1944: Reconnaissance of New Guinea commenced every 10 days using "Dinah".

March 30, 1944: Engaged in patrol and search operations over the waters north of New Guinea following the Palau Air Raid. Operations continued until the alert was lifted on April 8.

April 9, 1944: Ordered to advance into New Guinea; moved to Wakde Island Airfield off the coast of Biak Island. Began patrols on the 13th.

April 22, 1944: Ground operations began in Hollandia.

May 4, 1944: Reconnaissance of Hollandia after its fall; reported on the status of airfield repairs.　　　　　

Around this time, the Sento 311 Hikotai was incorporated, forming a mixed fighter-reconnaissance unit. 

Early May 1944: Withdrew to Sorong (Jefman) Airfield, the westernmost point of New Guinea. Avoided the ground battle on Wakde Island that began on the 18th.

May 25, 1944: Incorporated 12 aircraft from the 201st Kokutai, which was undergoing training in Davao.

May 27, 1944: The "First Operation Kon" was launched (Operation Kon was a three-stage Japanese military operation designed to support the Battle of Biak Island). Engaged in air patrol until the order to cease operations on June 3.

Dispatched two fighters from the main force to escort the 24th Sentai bombing enemy positions on Biak Island.

June 5, 1944: "Operation Kon II" launched. Resumed patrol duties along shipping lanes.

June 7, 1944: Ordered the entire unit to withdraw to Kendari. Abandoned equipment and withdrew from "Operation Kon".

Thereafter, engaged in reorganization efforts.

July 10, 1944: A major reorganization of the kokutai was carried out. Placed under the direct command of the First Air Fleet and withdrew to Davao.

Transferred the Sento 311 Hikotai to the 201st Kokutai and incorporated the disbanded 251st Kokutai as Sento 901 Hikotai.

July 25, 1944: As the first batch of procured aircraft, four "Suisei" and nine "Gekko" arrived in Manila.

Throughout August, patrol operations were impossible due to a shortage of aircraft, so the unit focused solely on analyzing intelligence from the Army’s 15th Sentai.

September 1, 1944: Air raids on Davao began.

September 2, 1944: Another air raid on Davao. Four "Gekko" engaged the enemy. Three "Suisei" began patrolling for enemy task forces.

September 9, 1944: During the air raid on Davao, the "Gekko" used Type 3 cluster bombs but failed to shoot down any enemy aircraft, resulting in the loss of all aircraft.

Mid-September 1944: Two "Suisei" and eight "Gekko" aircraft advanced to Nichols Airfield on Luzon Island.

Upon arrival, both the "Suisei" and six of the "Gekko" aircraft were unable to conduct patrols due to mechanical failures. Patrols were carried out with the remaining "Gekko".

September 21, 1944: During a pursuit following the air raid on Manila, the enemy fleet was discovered; one aircraft was lost.

September 22, 1944: The remaining one aircraft guided the Zero Fighter Squadron of the 201st Kokutai.

October 27, 1944: The Davao detachment began supporting "Operation Tago" (a joint operation by the Japanese Army and Navy to transport reinforcements to Leyte Island during the Battle of the Philippines).

Late November 1944: Ran out of aircraft.

January 9, 1945: The First Air Fleet was ordered to withdraw to Taiwan.

The vast majority of the 153rd Kokutai personnel were unable to evacuate to Taiwan during the rescue operations that continued until February 10th, and were left behind in the Philippines. The 15,000 aircrew members of all the air units that could not evacuate formed the "Clark Area Defense Unit" under the command of General Sugimoto Ushio, commander of the 26th Air Fleet, and were deployed to ground combat under the 2nd Tank Division of the Army. Commander Wada Tetsujiro, who was in command of the 153rd Kokutai personnel on the ground, died of illness on October 29th after the surrender and did not survive to return home.

Mitsubishi G4M "Betty", 705 Kokutai, New Georgia

A set of photos features a Mitsubishi G4M1 Model 11 "Betty" found wrecked and abandoned in New Georgia belonging to the 705 Kokutai as the tail marking "336" indicates.

The unit was originally called Misawa Kokutai but on November 1, 1942,...(unit history relative to the photos, from Wiki)

...was redesignated to 705th Kokutai (Air Group). 

On 11 November, newly promoted Lieutenant Commander Nakamura led 16 torpedo-armed bombers against the enemy ships around Guadalcanal. They were intercepted by 16 Wildcat and eight Bell P-39 Airacobra fighters and in combination with AA fire from the ships, they shot down 11 medium bombers, while the rest returned severely damaged. This put an end to further raids by medium bombers against Guadalcanal. 

On 29 January 1943, 705Ku was involved in the Battle of Rennell Island. Lieutenant Commander Nakamura led 16 torpedo-armed bombers against the enemy ships spotted near Rennell Island. They scored no hits and in return lost one bomber, however, subsequent attacks by other air groups managed to sink the cruiser Chicago. 

On 12 April, the unit participated in Operation I-Go, where Lieutenant Commander Nakamura led 27 bombers against Port Moresby. 

Two days later, they also participated in a raid against Milne Bay. The unit continued to be involved in the Solomon Islands campaign until 5 September, when it was withdrawn to Tinian.

Aichi D3A "Val" - 582 Kokutai

Three photos, again from here, feature an Aichi D3A2 "Val" Model 22. As before, the tag mantions that it was found by US Forces in Talasea Airield, New Britain in September 1944, but online sources mention that it was "abandoned at Hoskins Airfield". 

The tail marking "82-224" indicates that it belonged to the 582 Kokutai which was originally organized as the 2nd Kokutai. Here's a history of the unit from the Japanese Wikipedia.

The 2nd Kokutai was provisionally organized as a combined fighter-bomber unit on May 31, 1942, as the First Phase of the Invasion Operation was completed and preparations for the Second Phase were underway. Although its unit number was low, it was formed relatively late. Previous provisional air groups included pure fighter groups (such as the 3rd and the 6th Kokutai), long-range attack groups (such as the 1st and the 14th Kokutai), and local patrol and reconnaissance groups (such as the 32nd and 40th Kokutai), but the 2Ku did not belong to any of these categories. Composed of numerous carrier-based bombers and escort fighters, it was a unique land-based aviation unit designed to conduct close-range anti-ship attacks from forward-deployed bases. It advanced into the Outer South Pacific, the theater of the "Second Wave Invasion Operation", but the Allied counteroffensive began immediately upon its arrival. However, because the frontline Buin airfield was still under construction, the unit was forced to use Rabaul as its base. Round-trip flights to Guadalcanal, the theater of operations, were impossible with the Aichi D3A "Val". Furthermore, due to the retaliatory attack on Tulagi immediately after their arrival, they were forced to conduct one-way attacks, resulting in the loss of aircraft, and thus were unable to contribute as a combat force during the early stages of their deployment. Subsequently, they received reinforcements and operated in the Outer South Seas until their disbandment, becoming the main force of the Rabaul Air Group. 

1942

May 31: Unit established.

August 6: Deployed to Rabaul (15 Zero-type carrier-based fighters and 16 carrier-based bombers)

August 7: Surprise attack on Tulagi. Nine aircraft bombed surface ships off Tulagi; one destroyer was slightly damaged, and all aircraft were lost (2 shot down, 4 missing, 3 abandoned after emergency landings). The Aichi D3A "Vals" lacked the range for a round-trip, so from the outset, these were one-way attacks based on the assumption that the aircraft would splash-land and be abandoned. 

August 22: Part of the Zero Squadron accompanied the Tainan Kokutai’s Buna Detachment and advanced to Buna.

September 11: The Zero Squadron, in conjunction with the 6th Air Fleet, escorted a bombing squadron targeting Henderson Field and engaged in aerial combat. No combat results or losses for the 2Ku. 

September 28: The Zero Fighter Squadron advanced to Buka Island. From this time on, combined fighter-bomber raids were suspended, and operations were separated into daytime raids by the Zero Fighter Squadron and nighttime bombing by the land-based bomber units. The 2nd Kokutai’s Zero Fighter Squadron also participated.

October 3: The 2nd Division carried out its landing on Guadalcanal. The Zero Fighter Squadron engaged in air defense of the convoy.

October 7: Supported the transport of heavy weapons aboard the "Nisshin"; the Zero Fighter Squadron engaged in air defense. Two aircraft went missing due to rough weather.

October 8: Buin Airfield completed; fighter units deployed. The 6th and the 31st Kokutai followed to Buin.

October 20: Began support raids for the 2nd Division’s general assault on the 24th. The Zero Fighter Squadron sortieed daily.

November 1: Renamed the “582nd Kokutai" and reorganized.

November 11: Nine aircraft participated in the anti-ship attack the day before the Third Battle of the Solomon Islands. Engaged in aerial support for the naval battle the following day and the 17th Army’s general assault on the 14th.

November 15: An enemy airfield at Buna was discovered by an Army reconnaissance aircraft.  The 582Ku designated as the attack force. 

November 16: Enemy reinforcements approached Buna. Twelve aircraft participated in the 26th Naval Air Fleet’s anti-ship bombing raid, severely damaging three transport ships.

December 6: The 26th Naval Air Fleet attacked a transport convoy bound for Buna. Eleven aircraft participated.

December 7: The 26th Naval Air Fleet bombed enemy ground positions at Buna. Six aircraft participated.

December 27: Joint Army-Navy air operation. 12 carrier-based bombers from the 582Ku, 21 Zero fighters from the 204Ku, and 31 Nakajima Ki-43 "Hayabusa" (Oscar) fighters from the 12th Hikodan.

December 28: Buna falls; the Yokosuka 5th Special Landing Force is annihilated.

1943

January 2: Jointly with the 204th Kokutai, attacked a transport convoy off Cape Nelson, a cape on the north coast of Oro Province, Papua New Guinea.

January 14: “Operation Ke”, the largely successful withdrawal of Japanese forces from Guadalcanal, concluding the Guadalcanal Campaign of World War II,  launched. The New Guinea front stabilized.

February 1: 15 aircraft sortieed for the Battle of Isabel (The battle that took place during the retreat is often referred to as the Battle of Isabel Island). Lost 2 aircraft.

March 28: 18 aircraft attacked a convoy in Oro Bay, New Guinea.

April 7: “Operation I-Go”, the aerial counter-offensive by Imperial Japanese forces against Allied forces during the Solomon Islands and New Guinea campaigns, launched. Preparations for the Y Attack.

[14 April: Y1 and Y2 Attacks Milne Bay, 1943

On 14 April, attacks were carried out by land-based air units against Milne Bay and Rabi (the Y1 attack), alongside attacks by carrier-based aircraft (the Y2 attack). The force composition was as follows.

Y1 Attack Force

Close Escort: 204Ku (21 Zero fighters), 253Ku (17 Zero fighters), 582Ku (18 Zero fighters)

Attack Force: 705Ku (26 land-based bombers), 751Ku (11 land-based bombers)]

April 11: 22 aircraft sortieed for the Y Attack.

April 14: Sortied for the Second Y Attack.

April 16: Third Y Attack canceled; "Operation I-Go" concluded.

June 16: Battle of Lunga Point: 24 aircraft conducted anti-ship attacks. 13 aircraft lost.

June 30: Rendova Island landing begins. Bombed the anchorage with 8 aircraft until the following day. Lost 5 aircraft.

July 2: Ryuho aircraft squadron arrives at Rabaul. Subsequently, operated jointly with the Ryuho carrier-based dive bomber squadron.

July 5: New Georgia Island landing begins. Bombed the anchorage with 7 aircraft.

July: The fighter squadron was disbanded and reorganized as a pure dive-bomber squadron. The fighters and their crews were transferred to the 201st and the 204th Kokutai.

August 1: Bombed the anchorage at Rendova Island with 16 aircraft.

August 15: Enemy landed on Vella Lavella Island Island. Bombed with 25 aircraft.

September 4: Bombed a convoy off Salamaua with 8 aircraft.

October 15: Bombed a convoy off Buna with 15 aircraft. Lost 14 aircraft.

October 18: After the arrival of the 501st Kokutai in Rabaul, the 582Ku subsequently jointly operated.

October 25: Enemy aircraft attacked Rabaul. Participated in interception with 2 aircraft.

October 28: “Operation Ro” launched.

["Operation Ro" was an air operation carried out by the IJN in November 1943, ordered during the fighting that began following the Allied landing on Mono Island. The Japanese military, utilising land-based air units and the 1st Air Fleet attached to aircraft carriers, launched attacks against the Allied landing convoys approaching the vicinity of Bougainville Island and the fleet supporting them.] 

 On November 1, the 1st Air Fleet flight units arrived at Rabaul.

November 8: Second Battle of the Bougainville Islands. 38 aircraft sortieed in conjunction with the 501Ku.

November 12: 1st Air Fleet withdrew.

November 17: 552Ku arrived at Rabaul. Thereafter, operated jointly.

December 15: Enemy lands at New Britain Island, Cape Marcus. Bombed with 7 aircraft.

December 17: Provided supporting bombing with 12 aircraft for the Army Landing Craft Task Force’s counter-landing at Cape Mercus.

December 21: Bombed a convoy off Cape Mercus. Operations  continued intermittently until the 31st.

1944

January 7: Air raids on Rabaul intensified. By the 19th, the number of carrier-based bombers had plummeted to 15.

January 25: 2nd Air Fleet advanced to Rabaul.

February 5: 552Ku withdrew.

February 20: 2nd Air Fleet withdrew.

February 28: 501Ku withdrew.

March 4: Disbanded.

Following the air raid on Truk Island on February 17, which severed supply lines, the decision was made to abandon the Outer South Seas. The 582Ku, which had remained in Rabaul since its deployment, was disbanded. After retreating to Truk, it transferred its remaining six Nakajima B5N "Kates" to the 551Ku.

Yokosuka D4Y "Suisei" (Judy) - 501 Kokutai

Two photos today from here feature a Yokosuka D4Y1 Model 11 “Suisei”  (Judy). As you can see the caption says that it was found by US Forces in Talasea Airield, New Britain in September 1944, but online sources mention that it was found "abandoned at  Hoskins Airfield on New Britain. During early May 1944, captured when U.S. Marines from the 1st Marine Division (1st MARDIV) occupied the area."

The tail marking "01-070" indicates that it belonged to the 501 Kokutai. Here's a history of the unit from the Japanese Wikipedia and the "The I.J.N. Carrier Bomber SUISEI D4Y Series photo & illustlated Part#1" by DNK.

The 501 Kokutai (501Ku) was a unit of the Imperial Japanese Navy. As the main torpedo bomber force defending the the front linesin the Outer South Seas, it engaged in torpedo attacks, bombing missions, and patrol operations in the Outer and Inner South Seas during the mid-Pacific War.

To replenish the depleted strength of the 582 Kokutai, which had been conducting bombing missions for nearly a year in the Solomon Islands area using Rabaul as its base, the 501Ku was established as one of the bomber squadrons forming part of the Outer South Seas land based air force. On June 30, 1943, the day before the unit was officially organized at Kisarazu Airfield, U.S. forces landed on Rendova Island, marking the start of a full-scale counteroffensive, and a rapid deployment to Rabaul was demanded. However, due to the unit’s recent formation and the fact that it was the first air group organized around the new “Suisei”  bombers, it was plagued by insufficient pilot training and early mechanical failures of the aircraft type, and the deployment to Rabaul was not achieved until October. 

1943

July 1: Formed at Kisarazu Airfield. Assigned to the 25th Koku Sentai of the 11th Koku Kantai. Training began at Kisarazu Airfield with 36 “Suisei” .

October 12: Training completed. An advance party of 17 aircraft departed for Rabaul, but turned back due to bad weather. The same happened on the following day.

October 14: Finally advanced to Iwo Jima, and via Truk, 14 aircraft completed their deployment to Rabaul on the 18th. Along the way, one aircraft remained behind on Iwo Jima due to engine failure, and two were severely damaged during landing at Truk.

At that time, the only carrier-based dive bomber unit deployed in the Southeast Area was the 582 Kokutai, equipped with Aichi D3A2 Model 22, and following the October 15 attack on ships in Oro Bay—where 13 of the 15 aircraft that took off, including the commander’s plane, failed to return—the unit had just relocated to Kavieng to rebuild its strength. 

The 501Ku was immediately thrown into action and began operations as early as the 20th. Three “Suisei”  took off from the Rabaul East Airfield starting at 03:00, conducting reconnaissance and daytime attacks on enemy convoys off Cape Cretin; however, they reported no results, and one aircraft, piloted by veteran WO Miyauchi Katsumi, failed to return. On the 22nd, two “Suisei”  conducted a reconnaissance and attack mission against ships off Cape Cretin. Additionally, during the day, four “Suisei”, together with 24 Zero fighters, were dispatched to attack enemy transport ships and destroyers navigating near Cape Cretin, reporting that one large landing craft had been severely damaged. 

On the following day, the 23rd, after conducting a reconnaissance and attack mission off Cape Cretin, four “Suisei”, in a combined fighter-bomber formation with 20 Zero fighters, again attacked the enemy convoy and escort vessels off Cape Cretin, scoring a near-miss against one destroyer.

October 27: Bombed an enemy transport convoy landing on Mono Island .

October 29: The 2nd Detachment of the 501Ku took off from Kisarazu with nine “Suisei”, and on November 4, eight of them safely reached Rabaul and joined the ranks.

From November 5 until 11, the unit took part in anti-ship missions against the Allied Forces that were taking part in the Bougainville Campaign in cooperation with the 582Ku.

As of December 1, the number of 501Ku aircraft stationed in Rabaul was 11, of which 5 were operational. Although some reinforcements were received, the unit never reached full strength and continued to dwindle; by January and February, it was finally reduced to a situation where only one to three aircraft were operational.

1944

February 1: Reorganized to a strength of 72 aircraft. Established a Truk Island detachment with 25 Zero fighters equipped for bombing missions.

February 17: Major air raid on Truk. The Truk Detachment engaged the enemy, losing 4 aircraft.

February 26: The main force at Rabaul made its final sortie, bombing a transport convoy off Green Island.

February 28: The main force withdrew to Truk. One operational aircraft flew back, while the commander and 6 crew members arrived at Truk on March 2 aboard the I-41 Submarine.

March 4: Assigned to the 26th Koku Sentai of the 14 Koku Kantai.

March 10: Main force completed transfer to Peleliu. Joined forces with the remnants of the 552Ku.

March 25: Dispatched training personnel to Davao.

March 29: Major air raid on Palau. Lost 12 Zero fighters and 9 carrier-based bombers.

March 31: 10 Zero fighters and 4 “Suisei” arrived in Davao from the home islands.

May 8: Remaining forces from Peleliu withdrew to Davao, joined the training unit, and continued training.

July 10: The 501 Kokutai is disbanded and survivors were incorporated into the 761 Kokutai to reinforce it in preparation for “Operation Sho.” ["Operation Sho-Go" was a plan devised by the Japanese Army and Navy during World War II to intercept enemy forces using base air units in the Philippines, Taiwan, and mainland Japan. The operations were numbered from No. 1 to No. 4 depending on the area of the main battle, and Operation Sho-Go No. 1 was launched on October 18, 1944, in response to the American invasion of Leyte Island]