Koko Kyouwakoku (Republic of Koko)

Kokoan light aircraft carriers of WWII:

Ahodori Class:

The two light carriers of the Ahodori class began their life as the fourth and fifth ship of the Hayabusa seaplane tenders (or better, seaplane cruisers) that Koko was building in the early 30's to circumvent the limitations of the LNT. The two ships, named Ahodori (albatross) and Fukuro (owl) had been laid down in 1934 and 1935 to the original specifications but were reordered as Light Carriers in 1936 under the second Rearmament Bill as Koko decided to denounce naval treaties. Works on the ships stopped until 1937 while the design was accordingly modified.
The hull was lengthened by 2,6m at the stern and all 140mm guns and superstructure deleted from the design. The original seaplane hangar was extended to a length of 113 meters thanks to the boiler exhausts being rerouted to starboard, its maximum width was 14,2m. A newer upper hangar was added on top of the former, 142m long and 17m wide at its maximum. Both hangars were 5,3m high. The original elevator well was raised up to the flight deck so that two lifts served the upper hangar and one the lower hangar. The layout was not optimal, but it was not possible to extend the forward elevator well down to the lower hangar because the hull was too narrow forward to house the motor and counterweight rails as well. To mitigate this issue the the original -now aft- elevator was modified into a doulbe deck unit. When at rest its two levels lined up with the flight deck and upper hangar. This made possible to lower the elevator down and load from both hangars and then, in a cyclic pattern, bring planes from and to the flight deck almost simultaneously. This allowed, by design, to operate an airwing of 18 Yokosuka B4Y torpedo bombers, 11 Aichi D1A2 dive bombers and 10 Mitsubishi A5M4 fighter planes for a total of 39 machines. A 189m long and 23,9m wide flight deck was added, with a distinctive overhang at the stern to maximize its length, giving the ships and overall one of 220,9 meters. The flight deck also housed two rectractable 110cm searchlights near the forward command station, a wind baffle, two crash barriers, seven arrestor wires and a foldable crane for aircraft handling. The 70mm side armor belt was removed, with the exception of two sections forward and aft to protect the torped and bomb bays. Armament-wise the original anti-aircraft armament of the seaplane tenders was retained in numbers, with four twin 127mm DP guns fitted on sponsons on both ides of the flight deck, two forward and two aft. In addition to them, eight triple 25mm machine guns were added amidship as well.
Ahodori, the lead ship and first Koko no Kaigun aircraft carrier, was officially launched in 1938 and commissioned by August 1939.
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Ahodori sea trails showed that the carrier behaved better than some similar IJN light carriers, mainly thanks tho less topweigh and more careful ballasting, and could make the same 34knots of their seaplane-tenders half-siblings. However, the forward end of the flight deck being really close to the forward lift created issues to aircraft operations and offered a small margin of error for any pilot who happened to overshoot the arrestor wires or the crash barriers. Given the fact that the carrier-based branch of the navy air service had just been established, with Koko's aircrews still extremely inexperienced in carrier-based operations, this happened more times that the Naval Staff was be comfortable of..
For this reason -other than toughening up training for the aircrews- between January and May 1940 Ahodori was refitted by extending the flight deck all the way to the bow, increasing its overall length to 218,8m.
Fukuro, Ahodori's sister, had been launched in December 1937, but her fitting-out lasted longer, as she was also given the extended flight deck before completion. She also had extended walkways on the starboard side and an enlarged radio-room on the port side which distinguished her from her sister. Fukuro was commissioned on February 6th 1941. By the time of her entry into service more advanced planes had become available, so that she carried 14 Nakajima B5N2 torpedo bombers, 8 Aichi D3A dive bombers and 11 Mitsubishi A6M2 fighter planes for a total of 33. 34 planes could be carried in some circumstances, but usually they were a tight fit as the forward 26 meters of the lower hangar were only 8,5m wide and could not fit anything other than a B5N with its wings folded. Thus this section of the hangar was almost exclusively dedicated to mainenance and workshop area and storage for disassembled aircraft spares, usually three.
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Ahodori and Fukuro formed, together with Koko's first fleet carrier -Umineko-, Koku Sentai 1 and were in the middle of the action since the very fist day of the war. On December 7th 1941 they attacked and bombed Midway island, specially carrying and extra complement of D3A dive bombers for the job. Later the same day, their planes stubmled upon those of the USS Lenxington in the first carrier battle of WWII. In the messy and confusing aerial fights Fukuro airwings scored no significant hits or kills, but put up an uninteded diversion that opened the path for Umineko's planes to catch the Lexington undefended and damage her forcing its withdrawal. Ahodori's planes instead were credited with the first kill of the war for Koko no Kaigun when they sank the US Destroyer Flusser (DD-368), which they found and attacked while cluelessly attempting to locate the Lexington later in the battle.
In the following months the two light carriers supported Kokoan operations in the Aleutians before taking part in the unsuccessful chase of the Doolittle Raid ships in April 1942 and the Kokoan raids on the French Frigate shoals and Aleutians of May 1942. Ahodori and Fukuro were deployed again in June for further raids against the Aleutians, also acting as a decoy for the US navy. The Americans were to be ambushed and disposed by another IJN/KnK combined fleet centered around the Kido Butai, which was waiting off Midway Island. Things did not go as planned, as thanks to their intelligence works the Americans knew in advance what was to come and were the ones that ambushed the Kido butai with disastrous results for the Japanese.
After the defeat off Midway, Ahodori and Fukuro kept operating in northern waters for the next five months, during that time they were joined by the newly built light carriers Tobuio and Ajisashi, and assigned to the newly formed Koku Sentai 2.
After a quick stop at Toumachi to embark A6M3s and Okajima D4O1 dive-bombers in place of the older A6M2s and D3As Ahodori and Fukuro finally reached the Solomon Islands theatre in november 1942, taking part in the aerial phase of the Third Naval Battle of Guadalcanal. The light carriers remained operational in the Solomons for months to come, executing raids on US-held positions and attacking shipping lanes, then partecipated in the battle of Torres islands taking credit of the sinking of the US escort carrier Altamaha and damaging Recerchean CVL Peppermint Bay. Fukuro suffered sligth damage from a near-miss during the battle. The two again engaged enemy units on June 26th 1943 in the Solomon Sea, when they twarthed and Allied carrier raid against New Georgia. By early 1944, the two ships were the only Kokoan carriers still operating in the Slomons Islands. On February 2nd, they engaged once again enemy carriers at Stewarts Island, the third consecutive battle they fought that ended indecisively. By this time however, both Ahodori and Fukuro had accumulated enough battering to warrant a respite after fifteen months of continous deployment. Furthermore, during the last battle Ahodori had been hit by a bomb on the flight deck which, while causing manageable damage, still required repairs to be done in a shipyard, Fukuro instead needed to replenish its airwing to replace combat losses.
Both returned in home water were they recieved their fist major wartime refit: Lower deck portholes were closed over and anti-air armament augmented with the addition of four extra triple 25mm machine guns, plus another three fixed and eight movable single mounts. Red and white stripes on the aft flight deck were removed, leaving only those on the outrigger platforms, and the wooden plaking part painted dark to reduce visibility from the air. Radars were added, with Thiarian R4CA fire control ones added on the 127mm gun directors, plus a Type 13 air search set on the forward mast and a Type 21-mod7 antenna on the flight deck edge on the port side in a retractable mount. The airwing as updated by embarking the Tokuda A7T2 fighter, which superseeded the Zero in kokoan frontline carrier service. In addition to that, B6N2 torpedo bombers replaced the older B5Ns, total aircraft carried became 35, up two machines compared to 1941.
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In this guise Ahodori and Fukuro, now sailing together with the entire Kokoan carrier fleet met the US Navy off Laysan atoll. together they sank one American light carrier and a Battleship, but suffered again large losses within their airwings, forcing them to return to Toumachi for further training. The next battle that Ahodori and Fukuro took part in was also the last the two ships fought together. On September 10th 1944 During the second battle off Midway, Ahodori suffered a direct torpedo hit early in the battle and began taking on water. As the battle evolved disastrouly for Koko no Kaigun the crippled Ahodori became a prime targed for American dive-bombers during the Kokoan retreat. Hit another four times and set ablaze, Ahodori sank stern first, taking with her 602 of her complement of 875 men.
Fukuro had suffered two bomb hits during the battle, but survived thanks to her damage control crew. Upon returning to Koko she was repaired and refitted again. She was bulged, adding 2 meters to her beam, to increase stability and improve anti-torpedo protection. The loss of speed from 34 to 33 knots was deemed acceptable. Anti-aircraft armament was vastly expanded by fitting four 28-barreled rocket launchers in pairs towards the stern, machine gun tally reached twelve triple, six twin and twenty-five single 25mm mounts, plus another five dismountable ones, for a total of 78 barrels. Radar suite was updated by fitting newer R12CAD anti-air fire control radars, and Type 24-mod2 air-search mattress, plus a Thiarian R6R direction finder. The airwing was renewed as well, but the old carrier was unable to operate most of the latest aircaft models both the IJN and KnK had in their inventories. The Aichi B7A dive/torpedo bomber was too long to fit into the elevators. Neither the Mitubishi A7M2 fighter, the soon to enter service Tokuda B8T torpedo bomber or upgraded D4O2 dive bomber could be carried as they were too heavy to land back unless the entire arrestor wire and crash barrier system was completely replaced. Fukuro thus had to stick with the already embarked D4O1 and B6N2, augmented by the new A7T3 fighter.
In an attempt to allow the Nakajima C6N reconnaissance plane to be operated (its not foldable wingspan being too large to fit into the elevators) and increase the offensive potential of its carriers Koko no Kaigun tried to experiment with deck parking. In the case of Fukuro herself, the narrow flight deck made this difficult, so that only six planes, usually four A7T3 for combat air patrol and two C6N for reconnaissance, were parked on the deck. Allowing to carry a total of 20 A7T3, 11 B6N, 5 D4O1 and 2 C6N for a total of 38, plus 5 disassembled spares. More than in 1941 but still short from the original 39. Lastly, the ship was completely painted in a two-tone blue scheme in an attempt to reduce visibility in the open sea.
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Fukuro, like all other Kokoan carriers, remained in home waters training its aircrews until June 1945, when it took part in the battle of the Philippine sea. A tactical success for the Kokoan/Japanese fleet, but a strategic defeat as well. Fukuro suffered no damage in the engagement, and returned home until October, when she departed again to join Jisaburo Ozawa northern force in operation Sho-Go, collecting every operational aircraft carrier the IJN and KnK still had at their disposal to oppose US invasion of the Philippines. The carrier vs carrier engagement, known as the battle of Cape Engano, resulted in a crushing defeat for Koko and Japan, with half of the aircraft carriers involved sunk and all others damaged. Casualties in the airwing was monstrous as well. Fukuro herself was battered heavily, losing nearly all of its planes and suffering three direct bomb hits that buckled the flight deck and set a fire in the upper hangar. Luckily, the two next US air attacks focused on Shinano so the crew was able to put out the fire. Fukuro suffered further near-misses later in the battle but was able to retreat. Upon her return to Koko she was slated to underwent major repairs but the start of the Uprisings made this impossible. Despite she fell into Loyalist control in Toumachi harbor, her damaged flight deck, internal damage and depleted airwing made it impossible for the loyalists to use her effectively against the rebels. After the Armistice she was temporarily interned to Midway, then recieved makeshift repairs after the end of the war and operated as a repatriation ship until she was decommissioned in 1947 and scrapped shortly after.

Ships in class: (laid down-launched-commissioned - fate)

Ahodori 1934-1938-1939 - Sunk 1944
Fukuro 1935-1937-1941 - Decommissioned 1947

Tobiuo Class:

Tobiuo (Flying Fish) and her sister Ajisashi (Tern) were Koko's next step into quickly building a respectable carrier force in the years preceding WWII. Their design phase did not start as full fledged light carriers however.
By 1933 the Naval staff had already requested for another treaty-skirting unit similar to those of the Hayabusa class 'seaplane tenders', so designers focused on giving the fleet a submarine tender that could be easily repurposed in other ways had the situation of the treaty limitations changed in one way or the other. The intent in this case was not to double up as a cruiser with a large reconnaissance airwing, but being converted into an aircraft carrier on a short schedule.
The design, completed by 1936 and budgeted for two ships named Same (shark) and Tako (octopus) called for a huge submarine tender 228,2m long, with a beam of 19,6m and a draft of 7,2m displacing 13.809t standard and 16.407t at full load. Four oil-firing boilers powering four geared turbines for a generated power of 70.000 shp would have driven four screws for a top speed of 28,5 knots. The engine room layout allowed for the number of boilers and engine power to be doubled in an eventual carrier conversion. Endurance was to be 7.600 nautical miles at 16 knots.
Two hangar decks were included in the design. A lower one, 79m long and with a maximum width of 13,8m, serviced by an elevator flanked by two large cranes -that doubled up as both aircraft and boat handling- and two type2 catapults. And an upper one, 45m long and 16,9m wide maximum that opened aft on the aircraft handling deck. The lower hangar would have fitted 4 Kawanishi E7K and 4 Nakajima E8N for reconaissance duties. The upper hangar would have housed four of the, then under developement, Watanabe E9W seaplanes as replacement for any losses suffered by the submarines. Large storage spaces forward were dedicated to maintenance workshops and supply holds for the submarines, plus a full stock of 86 torpedoes and up to ten periscope sets. All those spaces were designed to allow the hangars to be exapanded in the event of a carrier conversion. Fuel tanks also had a total bunkerage capacity of 5.400tons of oil to refuel Submarines. Those as well designed to be easily modified into fuel bunkers for the ship and avgas tanks for aircrafts.
The ship was to be armed with six 127mm/40 DP guns in three twin mounts, one on each beam just aft of the bridge ond one aft on centerline above the upper hangar. Twelve 13mm/76 machine guns in three quadruple mounts would have made up for the light anti-air protection. The only armor protection included initially was 30mm for the ammunition hoists and 50mm for the magazines. Crew was planned as 772 officers and men.
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The design was approved and budgeted in 1936, with both ships to be built at Yamatogawa Shipyards, but that very same year the Second Rearmament Bill was passed by the government, which included the denunciation of all treaty restrictions. It was thus decided to refine the conversion plan and laid down the two ships as light aircraft carriers from the start. Design went on in parallel to that of the larger fleet carriers of the Umineko class, and clearly showed its evolution lineage from that of the preceding Ahodori class. Being longer, beamier and with a deeper draft the new carrier would have been a more capable vessel.
Addition of a 227,9m long and 24,8m wide flight deck brought the total length of the ship to 230,2 meters. Waterline beam was slightly increased to 19,9m, while underwater anti-torpedo protection bulges actually got the full beam to 20,8 meters. In all displacement increased to 14.964t standard and 17.012t at full load. The machinery was now planned at its maximum output, with 8 boilers for 140.000shp, which coupled with the addition of a straight bulbous bow to the design allowed to reach a top speed of 34knots. Range was 9.200 nautical miles at 14 knots.
The ship had two full length hangars, the lower one was 150,7m long and 15,4m wide at its maximum, the upper was 151,7m long and 18,3m wide. Both hangars were 5,3m tall and both were serviced by two elevators. The forward elevator was 12m long and 13,5m wide, while the aft one was 11,7m long and 13,8m wide. The aft elevator was of a doulbe-deck design similar to that of the Ahodori class. The standard airwing was initially planned at 17 Mitsubishi A5M4 fighters, 10 Aichi D1A2 dive-bombers and 18 Nakajima B5N2 torpedo-bombers -with Mitsubishi A6M2 and Aichi D3As replacing the first two types by the time the ship entered service- for a total of 45 machines. Three disassembled spares could have been easily carried and stored in the lower hangar. For flight operations the flight deck was fitted with seven arrestor wires, two crash barriers and one wind break.
Protection consisted of a 35mm deck (cohinciding with the lower hangar deck), a 70mm box around bomb and torpedo magazines and an internal 25mm torpedo bulkhead that backed a 1-meter void bulge on each side. Anti-air armament was made of eight 127mm/40 guns in four twin mounts and thirty 25mm/60 machine gun mounts in ten triples. Total complement was 956 officers and men.
The two planned ships were renamed Tobiuo and Ajisashi, but remained officially budgeted under their old name and submarine tender designation as to hide from enemy intelligence the true number of aicraft carriers Koko no Kaigun was building.
Built at Yamatogawa, Tobiuo was finally laid down in december 1937, launched in 1939 and commissioned in late january 1942. One late modification, implemented when the ship was already under contstruction, was the addition of a small two-level island in place of the starboard side command platform. This also involved the relocation of the navigation bridge from the front of the superstructure under the flight deck (like on the Ahodori class) to the new island structure. The old bridge area was turned into extra officers space.
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After completing training for her aircrew Tobiuo was initially deployed to the Aleutians to ferry aircrafts and provide some extra air-power if needed, but the way US forces in the area had been thrashed during the previous months meant that she saw little to no action during her stay. The carrier returned to Toumachi, then departed for Singapore on april 15th, only to reverse course three days later as soon as news of the Doolittle raid spread, taking part in the vain attempt to hunt for hornet's task force. After four days of fruitless search Tobiuo resumed her course for Singapore, where she arrived on may 1st. Here she costantly harrassed Rechearchean naval forces in the Indian ocean, damaging multiple ships and sinking 3 cargo vessels. Her pilots were also credited of downing 81 planes in five weeks.
After the disastrous defeat the IJN suffered of Midway, Tobiuo left Singapore under new orders on june 14th and reached back Kokoan waters on the 23rd of the same month. At home she was joined by her sister Ajisashi, which had been commissioned in May 1942 and spent the last month and-a-half training aircrews, which included some of the first units of the new Okajima D401 replacing the older D3As. The two sisters were quickly deployed to provide air power along the western Hawaiian island chain and Aleutians if the Americans happened to attempt mounting up an offensive, something that was considered quite possible by Kokoan intelligence but ultimately never happened. .
In october, during a quick refit, Tobiuo recieved two extra triple 25mm machine gun mounts (Ajisashi had been built from the start with them) and both sisters replaced their A6M2 fighters with the new A6M3 model. Tobiuo also replaced all her D3As with D4O1s like Ajisashi had done earlier the same year. Joined by Ahodori and Fukuro and forming Koku Sentai 2 they reached the Solomon Islands theatre in november 1942, taking part in the aerial phase of the Third Naval Battle of Guadalcanal. The light carriers remained operational in the Solomons for months to come, executing raids on US-held positions and attacking shipping lanes.
Both sisters later took part in the Battle of Torres islands. Early in the fight Tobiuo planes damaged the USS Altamaha (later finished off by Ahodori and Fukuro), while Ajisashi squadrons crippled the Nassau. Shortly after however an attack wave from the HMRS Eyre and USS Enterprise managed to break the fleet combat air patrol and hit Ajisashi with two squadrons of dive bombers. Planes from the Eyre scored two bomb hits, while Enterprise did three, all landed in the aft part of the flight deck. The first two hits laid waste of the upper hangar setting up a fire, while at least one of thee Enterprise bombs penetrated deep into the bowls of the ship after smashing through the already damaged decks knocking out all four tubine rooms. The subsequent fire grew almost immediately out of control and led to the avgas tanks to ignite and torpedo magazines to detonate as well (it is not clear exactly which of the two actually went off first). Ajisashi blew up in a spectacular and terrifying fashion just 14 minutes after the attack taking with her all but 195 of her crew. The first Kokoan aircraft carrier lost during the war.
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Despite the pyrotecnic end of the Ajisashi the battle had still ended up with a Kokoan/Japanese victory, and Tobiuo herself had suffered no damage at all, which also allowed her to land some of Ajisashi's now orphaned planes. Returning to her role of aerial support in the solomons island area, Tobiuo was torpedoed by the USS Porpoise on June 14th. While damage was not so severe -the carrier easily made to Truk under her own power- it made her miss the battle of the Solomon Sea. Once repairs were complete she returned to Rabaul until early august when she was redeployed given the recent increased US activity in the northern Pacific. After replacing all A6M3s with the fresh into service Tokuda A7T1 fighter, Tobiuo took part in the Battle off the Frigate Shoals (also known as Battle off Gardner) on august 21st 1943, during which she took part in the sinking of the USS New York and later scored a few near misses on bot the USS Essex and Yorktown.
Finally, in early March 1944 Tobiuo recieved its major wartime refit. During works all portholes on the lower decks were plated over and the flight deck was painted over with dark grey to reduce visibility from the air. A type21-mod7 air search radar was fitted in a retractable mount on the port side of the flight deck aft. The ship also recieved a Type13 air search radar and two TypeR4CA air fire control radars of Thiarian design. The ainti-aircraft suite was increased to seventeen triple and eight single 25mm machine guns, for a total of 59 barrels. Nakajima B6N torpedo-bombers replaced the older B5N, and the newer and more reliable A7T2 took the place of the A7T1. Airwing increased to 49 planes, and was now made of 20 A7T2, 17 B6N and 12 D4O1.
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Sailing together with the entire Kokoan carrier fleet Tobiuo met the US Navy off Laysan atoll on may 15th, during which one American light carrier and a Battleship were sunk. Tobiuo suffered three near misses in return, but more importantly, she lost almost a quarter of her aircrafts to enemy figher and anti-aircraft fire. She the returned to Toumachi for repair and further training and replacement of her aircrew.
Called again into action on September 10th 1944 During the second battle off Midway Tobiuo was subsequently hit at least once during every attack wave the US Navy launched. Bomb and torpedo damage accumulated to eventually overwhelm the efforts of the damage control party to keep her afloat. Ordered abandoned later the same day Tobiuo slowly capsized to starboard and sank together with 248 men of her crew.

Ships in class: (laid down-launched-commissioned - fate)

Tobiuo 1937-1939-1942 - Sunk 1944
Ajisashi 1938-1940-1942 - Sunk 1943

Hario Class:

A new class of light aircraft carrier was requested by Koko no Kaigun in late 1940 as a war against the United States started to appear more imminent. Funding was aptly granted and design phase started at the earnest. Design phase was completed within a year, resulting in a vastly modified and improved Tobiuo class design. The new carrier was slightly shorter, at 226,5m overal length, but had a wider beam at 21,4m. Draft remained at 7,2m resulting in a displacement of 16.901t standard and 17.887t at full load. The bow was raised by the addition of an extra deck forward that increased crew space and improved seakeeping. The machinery remained the same at 8 oil-firing boilers for 140.000shp, which powered four geared turbines driving four three-bladed propellers. Top speed was 33knots given the increased displacement. Range remained 9.200 nautical miles at 14 knots thanks to the larger bunkerage. The ship had two hangars: the lower one was 141,9m long and had a maximum width of 15,5 meters, while the upper one was 146,2m long and 20,5m wide at its maximum. Both hangars were 5,3 meters tall and were served by two elevators. The forward one was 11,7m long and 13,2m wide, while the aft one -which was still of a double-deck design like in all previous Kokoan light carriers- 12,2m long and 13,5m wide. The flight deck itself was 224,2m long, 25,7m wide and was fitted with nine arrestor wires, two crash barriers and one wind break. A two-level full island with a slanted funnel was located on the starboard side of the flight deck just forward of midship. A first in a Kokoan carrier design.
Anti-air armament was made up by the, then under developement, 100mm/65 dual-purpose gun in four twin mounts, augmented by eighteen triple 25mm/60 mounts, totaling 54 barrels. Protection was significantly increased, and consisted of a 60mm deck (cohinciding with the upper hangar deck) plus a 100mm box around bomb and torpedo magazines. A35mm belt protecting machinery spaces extended below the waterline to double up as an internal torpedo bulkhead that backed a 1-meter void bulge.
Two ships were approved for construction in 1941, with four more added in 1942, all to be built at Yamatogawa Shipyards. The lead ship, named Hario (needletail), was laid down in early 1942, launched in 1943 and commissioned in may 1944. By that time the design was further modified with the addition of various electronics: A type21-mod7 and a TypeR2FA air search radars were fitted above the islands, while the 10mm gun directors recieved the Type R4CA fire-control radars. A TypeR6R high-frequency RDF was also added on top of the mast in addition to two standard sets. The airwing upon commissioning was made up of 44 aircrafts: 20 Tokuda A7T2 fighters, 15 Nakajima B6N torpedo-bombers and 9 Okajima D4O1 dive-bombers. Five disassembled spares were also carried on the lower hangar. Complement was 1.042 officers and men.
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Hario took part in the second battle off Midway on September 10th. The new and somewhat green-crewed ship achieved little, but also suffered almost no damage in return in a battle that saw Koko no Kaigun lose one third of its carrier force in a single day. Kept safe in home waters training its airwing Hario was joined by its sister Daisagi (great egret) in March 1945. Compared to Hario, Daisagi was fitted with more advanced Type24-mod2 air-search radard, typeR12CAD fire-control set and Type64 HFDF. In early june both ships had their airwing upgraded to 24 A7T3 fighters, 10 Tokuda B8T torpedo-bombers, 12 D4O2 and 4 Nakajima C6N reconnaissance planes for a total of 50 machines, 39 stored in the hangar and 11 permanently parked on the flight deck. Four disassembled spared were also carried.
Hario and Daisagi were then completely painted in a two-tone blue camouflage and took part in in the Battle of The philippine Sea in June 1945. Over the two-day engagement they damaged five US carriers. Daisagi escaped major damage while Hario was hit by a single bomb in the middle of the flight deck, which however did not penetrate the armoured hangar deck below. The subsequent fire was not severe and was put out within an hour. Overall, the battle was indecisive, a Kokoan /Japanese tactical success but an allied strategic victory as well, which in the long run held more weight as the invasion of Saipan could not be stopped.
Upon returning home both sisters were fitted with two 28-barreled 128mm anti-air rocket launchers. The light-anti-air armament was also increased to 84 barrels by fitting 30 single 25mm machine guns. The new improved D4O2 dive-bmber also replaced the older D4O1s.
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In october of the same year both sisters joined Ozawa's northern force during operation Sho-Go in an attempt to oppose the US-led invasion of the Philippines. During the subsequent battle of Cape Engano Hario and Daisagi had little to no fortune with their air attacks, which resulted in the slaughter of two-thirds of their entire airwing. American counterattacks damaged both seriously with multiple bomb hits, with Daisagi suffering the worst of the two. Despite that, they both managed to limp away from the battle, contrary to many other kokoan and Japanese carriers, and head home. Daisagi was further damaged on october 29 when hit by one torpedo from the USS Kingfish.
Upon their return to home waters Daisagi was declared a total loss. Despite her engines were still operational, the upper hangar had suffered extensive damage, the aft elevator was completely jammed and the flight deck was riddled with holes from bombs and shrapnels. Lenghty, extensive and complex repairs would have been needed to restore her ability to operate aircrafts. The uprisings that started shortly after in early November deprived the ship any chance left of being repaired. Hario was in better shape, and could possibly be patched up enough to be operational again, but given its depleted airwing it was decided to keep the damaged ship away from harm. Moved to a safe anchorage Hario was eventually sunk in shallow waters during the US bombing of Mitsuminato harbor in january 1946. Officially US forces had mistakingly believed the facilities and ships were in the hands of the loyalists instead of the rebels, although there is still debate up to this day if the bombing was really accidental or if the Americans were purposedly negating Koko of some leverage when it came to the peace treaty by removing an aircraft carrier from the tables.
Hario's wreck was scrapped in place after the war, while Daisagi recieved some minor repairs to make her engines more reliable. Ceded to the USN, the ship sailed to Bikini atoll where she took part in the nuclear tests of Operation Crossroads. Heavily damaged by both blasts (she was far enough from the explosions to not be in risk of sinking) Daisagi as eventually scuttled in open waters in September 1947.
Of the other four sisters ordered in 1942, Kounotori (stork), Nosuri (buzzard) and Hibari (skylark) all sat in various state of incompletedness. The first two were scrapped, starting in 1947, while Hibari's hull was launched in 1948 to clear the yards while she was awaiting disposal. The start of the Korean war in 1950 led instead to her life being saved, as she will be eventually completed as an helicopter carrier.
The sixth and final ship of the class never recieved a name and was canceled before being laid down in early 1946.

Ships in class: (laid down-launched-commissioned - fate)

Hario 1942-1943-1944 – Sunk 1946
Daisagi 1943-1944-1945 – Decommissioned in 1946, scuttled after Operation Crossroads in 1947
Kounotori 1944-1945-/ - Not completed
Nosuri 1945-/-/ - Not completed
Hibari 1945-1948-/ - Restarted as an helicopter carrier in 1950
unnamed – Canceled before being laid down in 1946

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