Ys I: Ancient Ys Vanished

Ys I: Ancient Ys Vanished, also known as Ys: Ancient Ys Vanished - Omen, Ys: The Vanished Omens, Ancient Land of Ys or simply Ys (Japanese title: イース), is a 1987 action role-playing game developed by Nihon Falcom. It is the first installment in the Ys series. Initially developed for the PC-88 by Masaya Hashimoto (director, programmer, designer) and Tomoyoshi Miyazaki (scenario writer), the game was soon ported to the Sharp X1, PC-98, FM-7, and MSX2 Japanese computer systems.

Set in a land called Esteria, the story centers around the titular civilization called Ys, which had mysteriously vanished 700 years ago with only traces of its existence being kept within the game's six books. When it is prophesied that an impeding darkness would come to threaten Esteria, a young and adventurous warrior named Adol Christin is called forward to collect these six books to aid him in vanquishing the darkness.

Ancient Ys Vanished saw many subsequent releases, such as an English-language version for the Master System and an enhanced remake for the TurboGrafx-CD system as part of a compilation called Ys I & II, alongside its 1988 sequel Ys II: Ancient Ys Vanished – The Final Chapter. It was also adapted into an OVA series Ys. DotEmu has released the game on Android with the following localizations: English, French, Japanese, Korean, Russian, Italian, German, and Portuguese. A Nintendo Switch port of the game, based on the original PC-8800 release, was released in February 2024, 37 years after the game's initial release.