Battlecruiser / Fast-Battleship Amagi:
Under the Hachi-Hachi Kantai plan, the IJN request for a class Battlecruisers was approved in late 1917: Four ships were to be built, named Amagi, Akagi, Takao and Atago.
The ships had a planned standard displacement of 41,217t and 47,000t at a full load. 250m long at the waterline, and 251,8 m overall, a beam of 30,8m and a draft of 9,5 m. Turbine engines driving four propeller shafts were powered by 19 Kampon water-tube boilers, eleven of them oil-fired, the other eight mixed oil and coal. This system was provided 131.200 shaft horsepower for a top speed of 30 knots. The planned fuel stores amounted to 3.900 tons of oil and 2.500 tons of coal, giving the ships a maximum range of 8.000 nautical miles at the planned cruise speed of 14 knots.
The ships were equipped with a main battery of ten 409mm/45 guns in five twin turrets arranged along the centerline: two superfiring turrets fore and three in line aft of the superstructure with one of them superfiring. The guns had a rate of fire between 1,5 and 2,5 rounds per minute and had a maximum elevation of 30 degrees, allowing a range of over 32.810 yards (30 km).
The secondary battery consisted of sixteen 140mm/50 guns mounted in casemates. The guns had a maximum elevation of 25 degrees, which enabled a maximum range of 19.140 yards (17,50 km). Four 120mm/45 anti-aircraft guns were fitted on the main deck at. Armament was rounded out by eight 24 in (610 mm) above-water torpedo tubes.
As planned the Amagi class was protected by an angled main belt 254 mm thick, sloped at 12 degrees, and a torpedo bulkhead 73 mm thick. The main battery barbettes had between 229 and 280mm of armor plating, with turret faces beign 305mm thick. The conning tower armor ranged in thickness from 76 mm to a maximum of 356 mm. Deck armor was 98 mm thick.
Akagi was the first ship of the class to be laid down; construction began on 6 December 1920 at the naval yard in Kure. Amagi followed ten days later at the Yokosuka naval yard. The projected completion dates for the first pair of ships were December and November 1923, respectively. Atago was laid down in Kobe at the Kawasaki shipyard on 22 November 1921, and was projected to be finished in December 1924. Takao, the fourth and final ship of the class, was laid down at the Mitsubishi shipyard in Nagasaki on 19 December 1921, and was also projected to be completed in December 1924.
The Washington Naval Treaty, signed in February 1922, threw the Japanese plan into jeopardy, but also led the involvement of Koko in it, which would drasticaly change the fate of one of the foru ships. As much as it greatly reduced the tonnage allowed for capital ships in the signatory nations, with a moratorium on new warship construction, the Treaty also allowed both Japan and Koko to complete one warship over 35.000tons each that was currently under construction. Having no warships under construction to fullfill the allowances, Koko was ultimately allowed the transfer of one of the Capital ships under construction in Japan after a tense and lenghty negotiation at the tail-end of the WNT convference. With the IJN immediately choosing to complete Tosa as a battleship, Koko would have been granted one out of Kaga, Akagi or Amagi, as Takao and Atago were deemed not enough advanced to justify their completion..
Just days after the WNT ratification, a meeting between IJN and KnK Naval Staffs was called in Tokyo to decide the fate of the three ships. As the IJN, unlike Koko no Kaigun, was also allowed to complete two capital ships under construction the various Staffs were prone to complete Amagi and Akagi as carriers and to transfer Kaga to Koko no Kaigun upon completion. The fact that the USN and the RN were completing three and two 30+knot battlecruisers each led to the decision of granting Amagi to Koko, giving the two allies an extra fast surface warship at their disposal. In August 1922 the deal was officially made, with construction on the Battlecruiser immediately restarted at Yokosuka.
Amagi was launched in November 1922 at the presence of high officials from both IJN and KnK, the ship then starting her fitting out proceedings, with delivery to Koko no Kaigun planned for the first half of 1924.
On Saturday, September 1, 1923 the Great Kantō earthquake struck Tokyo area, seriously damaging Yokosuka Naval Arsenal facilities too. One of the dock cranes toppled over and crashed onto Amagi's quarterdeck, but the damage was assessed to be repairable. Still, works on the battlecruiser were halted as earthquake damage to the Naval Arsenal had to be repaired. Works resumed sporadically in december 1923, but did not proceed at full pace until 1925. Interestingly enough, both the Japanese and Kokoan Naval Staffs agreed that, had Amagi been allocated for carrier conversion, she would have been stll on the yards when the earthquake struck, which could have possibly led to a total loss of the hull.
Amagi was finally declared complete on January 1st, 1926, immediately setting out for her sea trails, reaching 30,14 knots during her third run off Tateyama. The ship then steamed for Koko, reaching Toumachi Bay in early April, where she was officially commissioned as Koko no Kaigun's Flagship on April 14th, 1926.
Manned by 1.562 officers and men the huge Battlecruiser became the most desired sea post for all cadets, and the focus of most recruiting campaigns, quickly gaining a sort of iconic aura even in the eyes of the civilian population. At the time of her commissionming Amagi outclassed by far every other Koko no Kaigun warship: she was nearly twice as big as the Yagumo class Battleships and five knots faster with similar operating endurance. Her main guns could threw more weight and over 5.000yards farther. Comparision with the Goryo Class Battlecruisers was even more amiss.
During the first years of her career Amagi had the strange distinction of forming her own single-ship Sentai. The battlecruiser Aomegami, which she was slated to be paired with, had blown up in october 1925, probably due to that improper cordite storage and handling. The gap in speed with the two Yagumos was also considered excessive by the Naval Staff to field all three units under the same battlegroup.
After the uneventful first years of the 30's, when the only events worth to be mentioned was Kii and Owari joining her Sentai, and Kii replacing her as Koko no Kaigun's flagship, Amagi was called into action on november 8th 1933. Some Rikugun soldiers attempted a coup against Minister of the Interior and former Prime Minister Kusako Morimoto. Amagi was performing gunnery drills off Toumachi bay and she got Immediately recalled to port. She steamed at full speed and docked in front of Koko no Kaigun headquarters with orders to protect the building in case the rebles had tried to storm it. As the coup was quickly foiled by KnR and IJA troops loyal to Morimoto, Amagi's crew was denied further involvement in the events. The ship returned to her routine duties until she was ordered to Toumachi naval Arsenal for her first major refit on January 5th 1935.
While drydocked her stern was lenghtened 8,5m and a clipper bow fitted, increasing overall length to 262,08m. Anti-torpedo bulges were added, bringing the beam to 34,6m. Like done on Inaba's refit a year before, a standard for all Koko no Kaigun capital ship refits, the original 254mm armor belt was removed and replaced by a new 356mm one. Diagonal bulkheads 152mm thick connected the belt with he main gun barbettes, upper belt was left at 140mm. Turrets had sighting periscopes and 10m rangefinders fitted, with the guns maximum elevation increased to 43°. Face armor was increased to 508mm, while sides, roof and barbettes themselves were left with the original armor plates 229 to 280mm thick. Deck armor was increased from 98 to 164mm, further extended aft over the steering gear with 55mm plates. Splinter plates 3mm thick were added behind the torpedo bulkheads, with another 37mm plate added inside the newly added torpedo bulges. Casemate guns were improved too increasing their maximum elevation to 30°, ammunition stowage was increased for both main and secondary armament. The original four 120mm anti-air guns in single mounts were replaced by eight 127mm ones in four twin mounts, and two quadruple 13mm machine guns were installed for light AA-defense. Both fore and aft superstructures were heavily rebuilt in order to house newer and more advanced fire-control equipment. Standard displacement increased from 41.217 to 48.582tons, with full load being 56.002t. This increased the ship's draft from 9,5 to 10,21m. The engines were also refurbished, all 19 older oil and mixed-firing boliers were removed and replaced by 12 newer and more powerful oil-firing ones, leading to the removal of the fore-funnel. Engine power increased from 131.200 to 150.000shp, allowing the ship to retain her 30-knot top speed. Endurance increased to 10.000 nautical-miles at a speed of 16knots. A catapult and a collapsible crane was fitted at the stern to operate two Nakajima E8N reconnaissance planes.
In early March 1937, works on Amagi were almost completed when the Naval staff decided to send the ship to Europe to attend and represent Koko at the forthcoming King George VI Coronation Review. The ship was thus undocked and all works deemed not necessary were stopped: she had yet to recieve most of her fire-control equipment.
On March 25th, 1937 Amagi departed Toumachi bound for Yokosuka were she docked on the 28th of the same month, testing her new engines in the process. Joined by the heavy cruiser IJN Ashigara, departed Yokosuka on April 3rd 1937, steamed to Britain via Singapore, Aden, the Suez Canal and Malta, utlimately docking at Portsmouth on May 10th 1937. The massive warship caused many western military figures to raise eyebrows with moderate concern on how fast Koko was closing the gap with other major powers.
After attending the review, on May 20th, Ashigara departed for Kiel, Germany. Amagi instead joined the Thiarian battleship LT Tuama and left Portsmouth on the 22nd, bound for the Atlantic Ocean. The two ships steamed to Thiaria, reaching Bauaine on June 12th. Amagi docked off Noyalo, where some high figures of the Thiarian Navy were allowed to tour the ship. After refueling operations had been completed, Amagi departed on June 19th, facing up the winter stormy water of Cape Horn and Magellan strait. Such a route led to her foredeck to be swamped almost all the time by rough seas, leading to significant leaks and minor flooding in some crew quarters at the bow. After crossing into the Pacific Ocean, Amagi briefly docking at Valparaiso, Chile, to fix some of the damage and do a after further refuel before setting to the sea again.
After steaming over 26.700 miles over the course of three months, effectively completing a World cruise, Amagi returned to Toumachi on July 9th, where she was welcomed with widespread celebration. Just days later she returned to Toumachi Naval Arsenal to complete her refit with the installation of the Type 94 fire control equipment.
Redesignated as a Fast Battleship, Amagi was ultimately completed and recommissioned on August 5th 1937. Assigned to Sentai 1 she became once again Koko no Kaigun's Flagship.
During the course of 1938 and 1939 Amagi made frequent trips to Japan and a few to China, often ferrying Rikugun troops as Kokoan involvement into the Sino-Japanese conflict began to increase.
In November 1939, she was replaced in her role of Fleet Flagship by the newly built Battleship Yashima, she thus returned to the yards for further works. During her second refit the quad 13mm machine guns were removed, replaced by twenty 25mm pieces in ten twin mounts, six fitted on platforms around the forward superstructure and four on platforms on the back of the funnel. An anti-air command post was added by enlarging the main rangefinder platform on the pagoda tower. Wind baffles were added around the battle bridge greenhouses and two lookout posts were removed, replaced by extra machine gun directors. Most importantly, to fix the seakeeping issues that emerged during ther world cruise in 1937, her clipper bow was replaced again with a much more pronounced and flared one based on that of the Owari, further increasing the overall length of the ship to 264,9meters.
Amagi was recommissioned by fall 1940 and assigned to Sentai 1 with battleship Yashima. In 1941 she was re-assigned to Sentai 2 with Kii and was soon joined by Owari. During the same year her airwing was upgraded from two Nakajima E8N to three Mitsubishi F1M.
Amagi was active in the Pacific War from its first very day, escorting Koko's carrier force in its attack of Midway Island. She was one of six Kokoan Battleships that shelled into oblivion US fortified positions on the island later the same day, paving the way for the amphibious landings that doomed what was left of the American forces despite their valiant and fierce resistance.
Soon after, Amagi returned to Toumachi for a short refit time, during which she was fitted wih a degaussing cable.
In early January 1942, Amagi was detached from Sentai 2 and sent to support the Japanese invasion of the Dutch East Indies together with Sentai 5 (a cruiser division) and a few Suirai Sentai (destroyer squadrons). While Patrolling off Balikpapan, on the night of January 25th, the ships engaged in combat a British and Recherchean formation on a bombardment mission of the Japanese beacheads. The British Battlecruisers Irresistible and Tiger were escorted by the Cruisers HMS Exeter and HMRS Ravensthorpe, plus half a dozen destroyers. While the cruisers and Tiger engaged each other in a more messily shootout, Amagi focused on Irresistible alone, diverting the British ship from firing at the Kokoan cruisers. The engagement between the two ships was swift and equally damaging. Amagi riddled Irresistible superstructure with shells, obliterating most of her fire control, but in return Irresistible knocked out of action both Amagi's forward turrets when her 16-inch shells almost pierced through Amagi's barbettes.
Long lance torpedoes from the Kokoan cruisers had wrecked havoc in the Commonwealth formation however, forcing Tiger to disengage, Ravensthorpe to take on water, HMAS Vendetta to blow up. Irresistible herself had suffered two torpedo hits from the Fujiwara. Blinded and flooding. The british battlecruiser joined the rest of her formation into retreat.
The battered Amagi returned to Toumachi where she was drydocked for repairs. During the works, her barbette armor was increased to 305mm and an Aichi E13A reconnaissance seaplane replaced one of the three F1Ms the ship carried.
By mid March 1942 the repaired Amagi was back in the Dutch East Indies, this time together with Kii, Owari, the cruisers Otonase, Minase and eight destroyers. Right in time to escort the Kido Butai for the raids against Allied shipping and naval bases around Ceylon. On April 6th 1942 IJN Cruisers Kumano, Suzuya and destroyer Shirakumo were conducting commerce raiding operations not far from Amagi's squadron. That evening a British recon plane from ADM Somerville fleet spotted two of the three Kokoan battleships and a CL, but, in an inexplicable mistake, identified them as the three Japanese vessels. Unaware of this, Somerville withdrew the carriers as night was approaching, but sent the Warspite and Tiger, with six Destroyers as escorts, to deal with the "Japanese" ships, in anticipation of an airstrike to be launched the following morning to mop up what would had been left. The British vanguard intercepted the Kokoan ships a little earlier than 4AM on April 7th, all for an unexpected rude awakening, as they soon found themselves under a hail of 409mm shells. In a completely unfair fight Amagi tore apart Tiger with five devastating salvos recieving only a single hit in return. Warspite managed to escape after exchanging shots with Kii, while Owari and the other Kokoan escorts joined late in the fight to target the retreating enemy Destroyers, of which two were sunk. Knowing well enough that there could have been British carriers in the area, Amagi's captain wisely orderd his formation to reverse course and make flank speed towards the Kido Butai as soon as the last shell was fired. When later on the same morning Somerville prepared to launch the planned airstrike, its recon planes only found the CAP of the Japanese carriers, which promptly shot them down. Thus putting an end to the massacre known as the Battle of the bay of Bengal.
Amagi, having suffered almost no damage in the engagement, escorted the carriers Hiryuu, Soryuu and Akagi for a further dash to the south: on April 13th the Recerchean port of Hopetoun was bombed by Japanese aircrafts. The raids resulted in damage to infrastructure, harbor facilities and a few RRN ships berthed inside the bay. Five merchant ships were also sunk, and another seven damaged. The attack also aimed at luring out a part of the Recerhean fleet in order to engage it in battle, splitting Recerchean war efforts on two fronts, Maddelenians and Thiarians on the west and Kokoan and Japanese on the East. The Recerchean fleet did depart, but worsening weather conditions caused by an incoming cyclone caused the fleets to miss each other, denying the Kokoan/Japanese formation to spring their trap.
Further operations in the Indian ocean were canceled after the Doolitle raid, Amagi and the other Kokoan ships were recalled back home. Amagi took the seas again in June 1942, beign part of Yamamoto's Main body Fleet during the joint Operation AL/MI. Due to the unsubstantial contribution of the Japanese and Kokoan surface fleet during the Battle Off Midway, the Battleship returned home without having fired a single shot. Amagi's uneventful life, like that of all other Kokoan Battleships, continued until late October 1942. Taking part in training excercises and harmless patrols with the Carrier fleet around Midway in fear of an US attack that did not materialize.
Finally, as the situation in the Solomons was deteriorating, Amagi departed Toumachi escorted by Owari, the cruiser Ayase and four destroyers. She reached Truk on November 10 and immediately prepped for action. Amagi took the seas the next day but her formation was too late to join and help Hiroaki Abe mission to bombard Henderson Field during the First naval battle of Guadalcanal. It was howerer on time to form-up with Nobutake Kondo ships at Ontong Java for a second attempt at rushing the Slot and shell the airfield. The second naval battle of Guadalcanal began with a lopsided engagement that left three US Destroyers sunk and one crippled fleeing the battlefield. Things further heated up when the USS South Dakota, after suffering various electrical failuers, sailed in front of the burning Destroyers lighting up herself for the Japanese ships to target her repeatedly, all while the USS Washington was creeping in undetected towards Kirishima. Shortly after, however, the US ship under ADM Lee's command was spotted by Amagi's group. As soon as Washington fired her first salvo against Kirishima, she was also targeted by Amagi and Owari. Aided by the fact the US ship had to switch targets to return fire, which slowed down her reaction, Amagi -and Owari- hit Washington mutiple times, forcing Lee to back off and leave the battle while being chased by four cruisers and four destroyers firing Long Lance torpedoes in its wake. Meanwhile, as a damaged Kirishima retrated under escort, Amagi and all other Kokoan and Japanese ships finished crippling South Dakota. The US Battleship absorbed such and enormous amount of firepower that, when her burning hulk finally sank in the morning it looked nothing like a ship and was virtually impossible to determine which of the attackers had actually dealt the killing blow.
After having some damage hastily fixed at Truk, Amagi was back at Guadalcanal a mere week later for the largest surface battle WWII had seen to that point: the Third naval battle of Guadalcanal. The huge slugfest saw both sides mustering as much surface ships they could get in that short time, and featured no less than 15 capital ships (12 Battleships, 6 on each sides, and 3 Battlecruiser) in total. Amagi, steaming in the left column of the Kokoan/Japanese formation, engaged the Battlecruiser USS Constellation. Recieving no less than 10 direct hits, Amagi suffered significant damage at midship between the funnel and the pagoda tower setting part of her superstructure ablaze. However she also managed to hit the enemy Battlecruiser twenty-five times in return, enough to put Constellation out of action and lead to its eventual sinking.
With the situation around Guadalcanal turning in Japanese and Kokoan favour, especially after a handy defeat inflicted on the Americans at Tassafaronga shortly after, Amagi returned home for much needed and deserved repairs. She was fitted with a set of Type22 surface-search radars around this time, in addition to four triple 25mm machine gun mounts at midship that increased the anti-air suite to 32 barrels. Her return was matched by a wave of popular enthusiasm and propaganda campaigns, with the Government vastly exagerating the already impressive wartime achievents of the ship to such a level that is seemed Amagi was almost single-handedly defeating the entire enemy fleet. With the repairs completed Amagi was deployed again in March 1943 to support the planned invasion of Espiritu Santo. After the inconclusive Carrier battle of Torres Islands forced the operation to be postponed, she sailed back to Truk where she remained until early July while waiting for the new push to happen. By that time renewed American presence in the Aleutians and the French Frigate Shoals dictated her return to Toumachi. Her subsequent deployment, while escorting the Kokoan carrier force in the Battle off the Frigate Shoals (also known as battle of Gardner) on August 1st 1943, was also uneventful, with the exception of some small splinter damage on her quarterdeck caused by a near miss.
Despite the propaganda exaggeration by Morimoto's government, Amagi had indeed been one of the most succesful capital ships on the Axis side, let alone WWII in general, having took part in sinking (Tiger, Constellation, South Dakota) or damaging (Irresistible, Washington) five different enemy Battleships or Battlecruisers, one of them all by herself. Such reputation made her a prime target of the Pacific Allied Command, which promised a commendation for whichever Submarine crew managed to sink "Slaggy Amagi", as Admiral Halsey "loved" to nickname her. The US Navy purposedly sent half a dozen submarines in rotation very close to Kokoan waters. Taking extra risks in the attempt of scoring a lucky kill.
On september 4th the USS Searaven sighted Amagi just off Tojima island, but the massive presence of Kokoan ships and aircrafts in the area forced the submarine to leave as to avoid being located, let alone attempting to close in. A week later the submarine was joined by the USS Sturgeon and, on the afternoon of September 17th they both spotted Amagi on an easterly course during one of her training and supply trips to Midway. Their positioning was bad and no attack was attempted, but both crews decided to stick in the area and try to wait for Amagi on her return leg. The third time almost worked like a charm. Early in the morning on September 19th they found themselves in an ideal attack position as Amagi, escorted by four destroyers, was steaming west. Positioned one to port and one to starboard of the Kokoan warships both submarines launched a full spread of six torpedoes. Kokoan lookouts were efficient and spotted the two spreads fairly quickly. Amagi and her escort were equally fast going into evasive maneuvers, but the spreads were fired well enough to warrant some hits. Two torpedoes from Searaven's spread found their mark on Amagi's starboard side. One right below the conning tower and another forward, right below the muzzle of turret 1. Damage led to widespread flooding of void spaces inside the bulges, with shrapnels puncturing bulkheads and leading to significant leaks into boiler room 1. Further flooding happened in the damaged storerooms forward and in the forward crew quarters when water started pouring in from damaged portholes on the third deck. One of Sturgeon torpedoes also hit, on the portside near the mainmast, but luckily for Amagi, it was a dud. The Battleship went down 3 degrees by the bow and developed a 9 degrees list to starboard as the crew immediately went into damage control mode and started counterflooding. Meanwhile the Destroyers started hunting the two US Submarines. Both mananged to escape the depth-charge barrage with minor damage. Sturgeon was however caught surfaced and hit again by Kokoan aircafts from Midway the next day, suffering significant damage and forcing her return to Pearl Harbor for repairs that lasted until November. With damage eventually put under control Amagi slowly steamed back to Toumachi and was drydocked for repairs. To improve anti-tirpedo protection the 3mm splinter bulkhead behind the main anti-torpedo one was backed up by a 25mm plate in every boiler room. All portholes on the third deck forward were sealed.
Fresh from repairs, the night of December 18th 1943, she unkowingly avoided another US sub roughly 60 miles southeast of Heian Island. The USS Apogoon was unable to get in a favourable attack position and quickly lost contact with Amagi and her escorts. A similar situation happened again on February 3rd 1944. The USS Aspro, fresh into her second patrol, sighted Amagi's squadron heading for Truk approximately 160 miles south of Nanto island. This time the US submarine almost managed to get into firing position but was detected by the escorting Destroyers and barely managed to escape two hours of relentless depth-charging. Troubled by a recent increase of enemy submarine sighting near Home waters, Koko no Kaigun higher ups decided to step up their ASW patrol schedule while Keeping Amagi and other valuable ships in port. Limiting training maneuvers to the safety of Toumachi Bay. Amagi eventually sortied again to screen the Carrier Force at the Battle off Laysan on May 15th 1944, just after her return she was drydocked for a major wartime refit that lasted almost three months.
During works most of her portholes were closed over to improve watertight integrity and the extra 25mm splinter plating backing the torpedo bulkhead was extended to the full length of the citadel. The pagoda tower was also extensively modified. The lower bridge level housing the secondary battery fire control was given a glass greenhouse. New radar, radio and equipment rooms were added, the flag station was lowered. Fire control platforms, anti-air command post and spotting top were all expanded. The 127mm DP gun fire control was standardized by replacing the split rangefider-director set at midship with an integrated one and recieved TypeR4CA fire-control radars of Thiarian design.Type21 and Type13 air-search radars were also installed. Turret n°3 recieved a 10m rangefinder to improve fire-control redundancy. Two 110cm searchlights were landed and the span of the aft tripod yardarms was reduced to improve anti-air guns field of fire. Light anti-air armament was increased to twenty triple, ten twin and twenty-three 25mm machine guns, for a total of 103 barrels. Crew increased to 2.260 officers and men.
The freshly refitted Amagi saw action once again on September 10th, escorting Koko no Kaigun Carrier fleet for another sortie against the US Navy. What would later known as the Second Battle of Midway ended up as a disaster for Koko, with one third of its entire carrier force lost in a single battle. Amagi herself was hit by a bomb that smashed through the forecastle and suffered a couple of near misses, but damage was taken under control fairly quickly.
While Amagi was being repaired the sinking of the Battleship Yashima, torpedoed on September 22 by the USS Archerfish south of Nanto Island, came as a shock news for Koko no Kaigun. It happened very close to the home islands, in supposedly safe waters, revealing the deficency of the Kaigun coastal patrol service to ensure protection of it's own fleet even after the changes recently made. Patrols, both naval and aerial, were re-organized and increased once again. All this, coupled with other recent increased losses in various theatres of operation, let to an ever increased resolve of keeping capital ships from harm's way and preserve them for larger, decisive, operations.
Amagi never left home waters until june 1945, when she was deployed with the bulk of the Kokoan and Japanese fleets at the Battle of the Philippine Sea. The largest carrier battle in history ended with a kokoan/Japanese tactical victory but an Allied strategic one as well, the latter holding much more weight given the current state of the conflict. Amagi provided anti-air fire coverage for the fleet and emerged completely undamaged from the battle. Starting on August 29th, Amagi began a five-week refit to upgrade her anti-air fire control, electronics and armament. Her entire radar and fire-control suite was removed. A Type24, Type2RFA air search radars and two Type33-kai surface search radar and auxiliary fire control radars were fitted. Type1RCD fire control radars for man guns and Type R12CAD fire control for anti-air guns also added, plus a TypeR6R high-frequency direction finder and a standard IFF set. The midship fire-control deckhouse was expanded to house new plotting rooms for electronics and the mainmast starfish was further cut down to improve anti-air weapons arcs of fire. Four casemate 140mm mounts were landed and two twin 127mm DP shielded mounts added, increasing the heavy anti-air battery to twelve barrels. All Amagi's twin and triple 25mm machine guns were removed and replaced by Type5 40/60 mm pieces in 24 twin and 12 quadruple mounts (a total of 96 barrels) plus 25 single 25mm machine guns. Most of the boat complement, with the exception of just a 9m rowboat and an 11m motor-boat, was landed. The recon airwing was upgraded to two E16A and on F1M floatplanes. Finally, she recieved the basic dark blue camouflage scheme of many late-war kokoan capital ships.
With works completed Amagi and her half-sisters Kii and Owari joined the Japanese Center Force led by Vice Admiral Takeo Kurita in Brunei. On October 22nd the fleet left the anchorage bound for Leyte during operation Sho-Go in an attempt to repel the Allied invasion of the Philippines. The enormous formation was strong of fourteen Battleships, fifteen heavy cruisers, six light cruisers and twenty-three destroyers. After surviving unscathed a submarine ambush the night between the 22nd and 23rd the Center force ships were repatedly attacked by US Carrier-based planed for most of the 24th with Kirishima sunk and Myoko forced to retreat. Amagi went through the day undamaged thanks mostly to her brand new and highly efficent, even so if compared to the standard 25mm suite still equipping most of the Japanese and Kokoan ships, anti-aircraft defence. After detaching four Destroyers to assist Myoko and recover the survivors from Kirishima, Kurita feinted a retreat, then reversed course, crossing the San Bernardino Strait unmolested during the night.
The morning of October 25th the Center Force took by surprise the US escort carrier groups that were guarding Leyte Gulf. As the Japanese engaged Taffy 3, the Kokoan charged Taffy 2.
Amagi, following the three Yashima class sisters in the battle line, opened fire on the US escort carrier USS Manila Bay. Her 409mm shells often went through from side to side of the unarmoured escort carrier but they still managed to inflict damage, which quickly added up so much it forced the US ship to slow down. Amagi leisury closed in and sank Manila Bay with a total of 12 409mm and 36 140mm shell hits. With all but one of Taffy2 escort carriers in sinking condition, Amagi, together with Kii, Omi and Mikawa turned their attention to the Thiarian Battleship Atharta, which had been involved in a succesful gunfight against Suruga. Amagi hit Atharta five times with her fist salvo damaging her aft superctructure. Outnumbered and suffering more damage from the other Kokoan ships the Thiarian Battleship had no other option but retreat, not before suffering three more hits on her superstructure from Amagi's fourth salvo.
At that point Amagi and the other Kokoan ships turned to the southwest in order to rejoin the IJN formation and engage both Taffy1 and the other half of the Thiarian squadron. Soon after, to the surprise of many, came the order to withdraw issued by Admiral Kurita. After long minutes of indecision, fueled by Admiral Jun Minasoko -commander of the Kokoan squadron- costantly radioing Kurita in a vain attempt to change his mind, the whole fleet turned north and headed back towards San Bernardino Strait.
As morale on board the Kokoan ships reached an all-time low the retreating Kokoan/Japanese fleet was intercepted by Admiral Lee's formation, strong of nine Battleship (seven American, two Recerchean) and two Battlecruisers, shortly after midnight on October 26. Lee almost achieved surpise on the battered Axis fleet. At night, radar-guided gunfire was the deciding factor, despite being actually outnumbered (and outgunned) Lee's ships reduced Musashi, Mutsu and Nagashiro into sinking condition before either the Kokoan or Japanese managed to react and effectively land shots on target with their own fire-control radars. In the utter chaos and confusion that followed, Amagi found herself out of formation together with the IJN Nagato and under fire from the Battlecruisers USS Constituition and USS United States. Bracketed by near misses Amagi had all of her floatplanes shot off clean of her deck by two of Constitution shells. Another shell destroyed the crew's mess between turret 2 and three. While some of the escorting Destroyers attempted to protect the two ships Amagi and Nagato focused their fire on the USS United States and managed to inflict 22 and 13 hits each. With vitals crippled, fire control knocked out and turrets out of action, United Stated started to burn and list to starboard before eventually capsizing. The pair of Axis ships switched fire and hit Constitutition six and nine times, inflicting enough damage to allow them to disengage and join the rest of the fleet in their escape, marking the end of the last Battleship vs Battleship engagement of WWII .
Overall, Amagi had been hit eight times by main caliber shells, which had deprived her of the spotter planes, rended three of her casemate guns inoperable, glanced her n°2 turret and dented her main belt. Her engines were still perfectly functional and, after some quick repairs, Amagi safely departed Manila on October 28th 1945, steaming directly for Koko and reaching Hoshiguma harbor early on November 4th. As the rift between the various Military and Government factions grew, Amagi remained on anchor in Hoshiguma harbor under the command of Admiral Minasoko. On November 6th, when Koko uprising started, Amagi opened fire and shelled the local detachment buildings of the Imperial Japanese Army. As the Kokoan battleship in better material conditions, Amagi and her crew immediately started to actively aid the rebels, providing gunfire support to most land operations around Hoshiguma, Shiromoto and Minatogawa. With nearly the entire fleet and more than half of the army sided with them, the rebel faction led by Foreign Minister Hikaru Arai, CiC Admiral Genzaburo Karasawa and General of the Army Jouji Yoshinori, enjoyed total naval supremacy, as the Imperial Japanese Navy seemed reluctant to engage their former Koko no Kaigun allies to help of Morimoto's Loyalists. Amagi was thus free to take part in the rebel push towards Toumachi, carrying out one Shore bombardment after the other with little to no impunity util late February 1946. She even enjoyed the luxury of having time to be docked at Hoshiguma Navy Yard to repair most of the damage suffered during the Leyte Gulf campaign.
Then, the Soviet Union suddendly decided to get involved in Koko uprisings by breaking the non-aggression pact that had been standing since April 1941. On February 28th the Russian Pacific fleet, which had nothing more than the cruiser Kalinin and 13 destroyers in its inventory anyway, started shelling Shirominato while a small fleet of transports prepared to leave Petropavlovsk carrying troops for the invasion. Moscow hoped to get its hands on Koko's northern islands and their oil reserves under the pretext it was helping defeating Morimoto's Loyalists.
Amagi, escorted by two light cruisers and eight destroyers, was immediately deployed north as a reportedly furious admiral Karasawa treathened to sink the Soviet ships one by one if necessary. The standoff lasted until March 5th, when pressured from the US and UK the Soviets withdrew their fleet. Another factor the Soviets would never be willing to admit was that Amagi outgunned Kalinin so much that any direct confrontation would had been nothing short of suicidal.
With the crisis resoved Amagi descended south as the rebels launched their final offensive against Morimoto's forces, which were barricaded in Fuyuki. After a week Morimoto committed suicide to avoid capture and nearly all loyalist troops and surviving IJA garrisons ceased hostilities. The armistice between Koko and the Allies was officially signed on March 22nd 1946.
The Americans did not trust the Kokoans particularly, but they had been impressed by the performance of the co-belligerent Thiarians at Leyte and decided they could use some of the Kokoan ships to their advantage. So Koko no Kaigun was allowed to retain an operational force of one battelship, one light cruiser and eight destroyers that had to respond to direct US orders. Amagi was chosen over the damaged Kii and Owari or the 460mm armed Omi and Mikawa, which the Americans would not allow the Kokoans to use under any circumstances. So Amagi became once again Koko no Kaigun flagship, or what little of it was left operational. Painted in standard USN Measure22 camo scheme with her name spelled at midship on each broadside, Amagi hastily recieved a few radio TBS and IFF antennas for the other allied ships to recognize her as friendly. She didn't carry recon floatplanes, just as an extra measure to ensure a pilot would not suddenly change his mind and dive on an American ship. Her aviation facilities were left in place, including a now useless catapult, to allow Kingfishers and Seahawks from other ships to be serviced if ever necessary. For that reason a small team of US sailors and mechanincs joined the crew, together with a dozen officers to monitor crew operations and relay orders from the rest of the fleet.
The Kokoan squadron had joined the US 5th fleet during the invasion of Okinawa by late April 1946. As Amagi used some Thiarian supplied and derived electronic equiment she was paired up with LT Caithreim. Admiral Halsey later claimed that he had a subordinate reminding him that they were on his side every five minutes to avoid ordereing them blown out of the water. Amagi provided anti-air and ground fire support until the end of the campaign in July, but she remained at anchor in Nakagusuku Bay, or Naval Base Buckner Bay as the US navy nicknamed it, well after the end of the war. Amagi finally returned to Toumachi in November 1946.
Under the terms of the peace treaty, signed on May 3rd 1947, Koko had to surrender, disarm or decommission, its entire fleet with the exception of a few units. Amagi was allowed to be retained in service mostly for flagship and training duties. During the second half of 1947 Amagi recieved an SG surface radar and a DAK-RDF. She also landed the aircraft catapult, with the floatplane deck now used for boat handling and stowage. Finally, all 25mm and twin 40mm machine guns and most of her now useless fire-control gadgets were removed.
Amagi's uneventful postwar routine in the renamed and reorganized Koko Kaijou lasted until mid January 1950, when she was drydocked for a more extensive refit. During works all remaining portholes on the hull were plated over. All search radars were landed and electronics were upgraded by fitting one AN/SPS-6 air search radar, one AN/SPS-4 surface search radar, an SM/CXBL height finder, four Mark57 gun directors, an 66AKJ TDY jammer, a TDYa jammer, two DBM/DBM-1 RDF, and two AN/SPR-4 ECM. All Type5 40mm quad mounts were replaced by twelve quad bofors with Mark63 GFCS and Mark 51 directors. The 110cm searchlights were removed and replaced by four US standard 36-inch searchlights. Extra radio antennas were added, while the entire mainmast above the starfish was removed. The entire casemate battery was landed and the mounts plated over, also removed were the 4,5m rangefinders for their fire control and the 1,5m navigation rangefinders. The ship recieved US built service boats and had the quarterdeck converted into a landing area capable of handling two Sikorsky H-5/S-51 helicopters. Completed in September 1950, with the Korean War now raging, Amagi was hastily readied for action and sent to suport naval and land operations during the UN offensive into North Korea. After the Chinese intervention forced UN troops to retreat south, Amagi was one of the first ships to reach station to enforce the blockade of Wonsan, expending her entire ammunition stock bombarding North Korean positions.
Even after having been replaced by Sagami as Koko's Navy fleet flagship in 1952, Amagi returned to the frontline at Wonsan until late May 1953. Back home again, while the crew toiled to make her ready for another deployment, the Korean War finally came to an end.
With the war over, the brand new Sagami in service, Omi and Mikawa reactivated, it was decided to withdraw Amagi from active service and repurpose her as a training vessel. Modifications were minimal at first, with the, still empty, casemate deck converted into extra bunk areas for cadets. By the second half of the 1950s Amagi had recieved a new AN/SPS-10 surface search radar, plus URD-4 TACAN, two DBM-1 RDF, and an SLR-2 ECM suite. Four quad 40mm bofor mounts at midship were removed in order to make space for four motor whaleboats an their davits. More modern inflatable rafts replaced the old flotation rafts and nets. After serving five years in this role, Amagi was ultimately decommissioned in november 1958 and placed into reserve after 32 years of service.
Amagi would remain in the mothball fleet for the next fifteen years. In 1969 it was even contemplated to reactivate her to provide shore bombardment in Vietnam in place of the, soon to be retired, Mikawa. Such thing however proved to be unpracticable. Amagi was finally struck from the Navy list in 1973. During the next two years, she was partially disarmed with the removal of all her electronics and 40mm Bofors. However, even before she had been officially paid off, plans were in motion to preserve the venerable ship as a Museum.
Between 1975 and 1979, while a now unused pier at the Yamasaki Naval Base was turned into what is now the Yamasaki Naval Museum, Amagi was drydocked for extensive maintenance works, refurbishment and repainting. All WWII-era equipment that was possible to recover from Kokoan military storage facilities was fitted back on board, including part of the fire-control suite, all Type5 quad 40mm machine guns and eight of the twelve 140mm casemate guns. In 1979, before her opening as a Museum, she was featured in the movie Fuyuki no 14-kakan (Fuyuki's 14 days) about the final days of Koko Uprisings (a remake, in which she appeared as well, was filmed in 2016 for the 70th aniversary of the event). Over the course of the years, more equipment was scavenged, restored or replaced by mock-ups and reproductions to bring the ship as close as possible to her late WWII appearance, with the exception of her all-blue camouflage, which was not replicated. To date Amagi had been drydocked for extensive maintenance in 1990, 2000 and 2010 and has seen minor refit and works in 1995, 2005 and 2015. Although her propellers have been removed during the last major drydocking in 2010 -one is on display on her quarterdeck, the others are stored- her engines are reported to be still well mainatained and functional. The possibility of fitting back the propellers to allow Amagi to move under her own power again for the 100th anniversary of her commissioning in 2026 keeps popping up from time to time. All main guns and turrets are still able to rotate, elevate and fire as well.
In addition to Fuyuki no 14-kakan, Amagi has appeared in half-a dozen WWII movies (Both US and Kokoan productions) standing for Kokoan or Japanese warships as needed. Plus countless documentaries and a couple of cold-war and modern movies where a big warship was needed for plot reasons. Worth of mention is 2010's movie Guadalcanal, which retells the chaotic naval battles of November 1942 near the namesake island. It has been, to date, the last time Amagi has moved under her own power. Filming also caused some ruckus around the Fuyuki area, as it involved Amagi firing her main guns multiple times at night during production.
Over 40 years after her opening she has proven to be quite a popular attraction, both for Kokoan and foreign tourists, casual ones or naval enthusiasts. Either for the cultural significance she has gained in Koko or for the historical value of being one of only four WWII Axis capital ships still in existence (the others being Caithreim, Zuikaku and Nagato) and one of the most succesful warships of World War Two. The Aichi E16A on display on her deck -moved inside the museum building in winter- is the only surviving example of such aircraft on display anywhere in the world.
Ships in class: (laid down-launched-commissioned - fate)
Amagi 1920-1922-1926 - Training 1953 - Decommissioned 1958 - Museum Ship 1979