Yamataian aircraft carrier Hotaru

Marking a radical departure from previous Yamataian aircraft carrier design, Hotaru was built with heavy belt armour and an armoured flight deck, reflecting the changing attitudes towards the utility of carrier-based aircraft in the Imperial Navy at the time. Hotaru was expected to not only survive multiple bomb, torpedo, or shell hits, but also continue fighting effectively afterwards. Laid down in 1941, the lack of resources in Yamatai due to the ongoing Chiseian commerce-raiding operations meant that construction was slow, and Hotaru was finally commissioned on 7 March 1944. She had a minimal impact on the war and mainly acted as a transport ship due to Yamatai's severe lack of pilots trained in carrier operations at that point in the war. Hotaru was the only Yamataian carrier to survive the war.

Hotaru was later decommissioned in 1952, but was recommissioned on 3 August 1957 due to the outbreak of the Dai Hoa Unification War and the Imperial Navy's need for a carrier in the unfolding Escaric Divide context. Between 1960 and 1965, Hotaru underwent a major four-year overhaul and modernization that enabled her to operate carrier-based jet fighters, and she served as the only carrier in the Imperial Navy during the remaining 20th century. In 2001, following the launch of the STOVL aircraft carrier Sayashi, Hotaru was decommissioned for the final time. Despite attempts to preserve the carrier as a museum ship, and after several failed attempts at selling the ship, including an attempt to sell the ship on MainIchi, Hotaru was ultimately scrapped in 2009.

The STOVL aircraft carrier Hotaru, the lead ship of the and commissioned in 2010, was named in honour of this ship.

Operational history
Commissioned on 7 March 1944, Hotaru mainly acted as a troopship and supply transport during the Hinomoto campaign because of Yamatai's increasing shortage of aircraft by that time in the war. After the Oyashima Armistice on 15 July 1944, Hotaru continued to be used in a transport capacity to support continued operations against Arshavat in Yamataian Nanyokuni until the end of the war on 17 January 1945. Hotaru was the only Yamataian fleet carrier to survive the war.

Hotaru was first decommissioned on 19 June 1952 as the Imperial Navy could no longer afford to maintain the ship due to reforms carried out under the Okabe Nariakira regime. The ship was supposed to be sold for scrap, and for a time there was a plan to sell the ship to Chisei for nuclear weapons testing. However, nothing was done with the ship for years and she remained docked at Shirada Naval Base. The sudden outbreak of the Dai Hoa Unification War in 1957 led the Imperial Navy to recommission Hotaru on 3 August 1957. A costly repair and refitting program was carried out, and Hotaru carried out the carrier operations that she was built for with leased Chiseian carrier-based jet fighters over a decade after she was first commissioned. Hotaru's air wing participated in some battles of the war in the second half of 1958, providing air support for the Three Powers Alliance forces as well as coastal interdiction operations against Hoaian supply lines. She was later used as a transport ship again as Alliance troops withdrew from Dai Hoa in 1959.

After the Dai Hoa Unification War, Hotaru remained the only carrier in the Imperial Navy. Between 1960 and 1965, Hotaru underwent a massive refit and reconstruction program in Mitakishima, costing around 3.6 billion En. An angled flight deck was installed, as well as a steam catapult, stronger arresting gear, reinforced hangar elevators, and a mirror landing aid, permitting the operation of modern carrier-based jet fighters. The island superstructure was replaced, and a lattice mast was fitted to support the new fire control system and radar suite. The ship's boiler capacity was increased, and internal electricity was converted to AC through the installation of four turbo generators and one diesel generator.

Between 1965 and 1975, the Hotaru's air wing consisted of carrier-based aircraft purchased from Chisei. In 1975, the Kawazaki Ki-40 Tengu became the first indigenous Yamataian fighters to operate on Hotaru since flight deck trials with the in 1944. In 1986, Hotaru was involved in the 1986 Crosswind Sea Incident, when fighters from its carrier wing engaged Hoaian fighters off Dai Hoa in support of a Yamataian spy vessel.

Despite numerous upgrades and life-extending packages, the advanced age of Hotaru's hull called into question her usability beyond 2005. In the 1990s, the Imperial Navy began a plan to replace the Hotaru with two modern STOVL carriers, which materialised as the. In 2001, the first Sayashi-class vessel was laid down, and on 19 June 2001 the Hotaru was decommissioned. Initially, plans were made to preserve the vessel as a floating museum dedicated to Imperial Navy Aviation. However, the plans fell through due to a lack of funding and the vessel was sold to the Nishi-Inaba Steel Company in Danbara for scrapping in 2009.

At the time of her decommisioning, Hotaru was the oldest aircraft carrier in the world, and she was also the last Second Escar-Varunan War-era vessel in active service in the world. In 2005, amidst the Imperial Navy's attempts to sell the vessel for scrap Hotaru briefly appeared on an online marketplace for 40 million En, but was eventually taken down as the marketplace prohibited the sale of arms. This began a minor scandal that saw a Junior Admiral fired from the Imperial Navy.

Hotaru's name was later reused for the STOVL aircraft carrier Hotaru, commissioned in 2010 and leading the.