Tristia of the Deep-Blue Sea(蒼い海のトリスティアAoi Umi no Tristia) is a PS2 and PC game, developed by Kogado Studio. This game is part of the Deep-Blue series along with the sequel, Neosphere of the Deep-Blue Sky(蒼い空のネオスフィア). The story has been adapted into an OVA, and has been released with a title of "發明工坊" in China, Hong Kong, Taiwan, U.S.A., Russia, and Poland.