In Japan, what title was Metroid Prime 2: Echoes released under?

In Japan, Metroid Prime 2: Echoes was released under the title Metroid Prime 2: Dark Echoes.

The game debuted in North America in November 2004 as Metroid Prime 2: Echoes, followed shortly afterward by European and Australian releases. Japan received the GameCube version on May 26, 2005, using the alternate subtitle Dark Echoes. The change distinguishes the Japanese market title but does not identify a different game or storyline.

The subtitle fits the game’s central premise: a meteor’s impact on Aether creates Dark Aether, a hostile parallel world. Samus must move between the light and dark versions of regions such as Agon Wastes, Torvus Bog, and the Sanctuary Fortress while recovering the Light of Aether from the Ing.

Dark Echoes is sometimes confused with Dark Aether, which is the name of the alternate dimension within the story, not the Japanese title. Shadow Echoes and Light Echoes are not official release titles. The game was later adapted for Wii in Japan as part of the New Play Control! line and included internationally in Metroid Prime: Trilogy.