Shiden Kai Exhibition Hall

The Shiden Kai Exhibition Hall (紫電改展示館) is located in Mase-yama Park in Ainan, Ehime Prefecture, on the island of Shikoku. It houses the only surviving Kawanishi N1K2-J Shiden Kai fighter aircraft in Japan — one of just four remaining worldwide.

The aircraft was assigned to the 343rd Naval Air Group (343 Kōkūtai, known as the "Sword of the Pacific"), an elite fighter unit formed in December 1944 under the command of Captain Minoru Genda at Matsuyama Air Base. The 343rd was the Imperial Japanese Navy's last dedicated interceptor group, equipped exclusively with the N1K2-J Shiden Kai — considered the Navy's finest fighter of the war, capable of engaging American P-51 Mustangs and F6F Hellcats on equal terms.

On July 24, 1945, the aircraft took off from Ōmura Air Base in Nagasaki Prefecture and engaged American carrier aircraft over the Bungo Channel between Kyūshū and Shikoku. During the dogfight, the plane sustained combat damage and the pilot was forced to ditch in the waters near Kura Bay. The pilot's identity remains unknown — six Shiden Kai from the 343rd failed to return that day, and it has not been determined which pilot flew this particular aircraft.

The wreck lay undiscovered on the seabed at a depth of approximately 40 meters for over three decades. In November 1978, a local fisherman spotted the aircraft on the ocean floor. On July 14, 1979 — 34 years after it sank — the plane was raised by crane and returned to the surface. Despite extensive marine growth, the airframe was remarkably intact: the cockpit canopy was open (suggesting the pilot attempted to escape), but no human remains were found.

After recovery, the aircraft was cleaned, treated against corrosion, and placed on permanent display. The four propeller blade tips remain bent backward from the impact with the sea — a deliberate preservation choice. The museum opened on May 1, 1980, on the hilltop of Mase-yama overlooking the bay where the fighter was lost. Additional exhibits include a diorama of a wartime air base, paintings of the Bungo Channel engagement, photographs of 343rd Kōkūtai pilots, salvaged aircraft components, and a Tenzan carrier attack bomber propeller.

Aircraft specifications: length 9.34 m, wingspan 11.99 m, height 3.9 m, weight 4,860 kg, maximum speed 620 km/h, powered by a Nakajima NK9H Homare 21 engine producing 2,000 hp. Admission has been free. Under an announced renewal plan the hall was scheduled to close from September 2026 and reopen around autumn 2027, so visitors should check its current status.