Mask of the Sun was released in 1993 and was one of two games released under the title of "Ys IV", the other being Hudson Soft's Ys IV: The Dawn of Ys for the PC Engine. The two games share the same basic story, but many changes were made in the Hudson-produced Dawn of Ys. Of the two, Mask of the Sun was the official Ys IV storyline before the release of Ys: Foliage Ocean in Celceta. Originally a version of "Mask of the Sun" was also planned by Sega for Mega Drive and later Mega-CD under the Sega-Falcom joint development agreement, but this version was ultimately canceled.