Reigo: The Deep-Sea Monster vs. the Battleship Yamato (深海獣レイゴー, Shinkaijū Reigō) is a 2005 independent tokusatsu film by Shinpei Hayashiya. Veteran artist Keita Amemiya designed the titular monster. The film's original working title was Reigo vs. Yamato (レイゴー対大和 - Reigô tai Yamatô).
The film, set in World War II, depicts the story of the real-life Japanese battleship, the Yamato, which is confronted in the Pacific Ocean by giant monsters, including the most fearsome of them all, Reigo.
In September 1942, Captain Yamagami (Susumu Kurobe) is ordered to rendezvous the Yamato with the Combined Fleet that is gathering at the Truk Islands (aka Chuuk Islands) in Micronesia, a key strategic point in the South Pacific. With beautiful clear blue skies above and surrounded by coral reefs below, this South Seas paradise became a strong base for the Combined Fleet and the front lines of the naval war; a place where many fierce battles were fought. Decades later, the sea bed surrounding the Truk Islands is still littered with the remains of more than 60 warships and airplanes.