Released in Japan by Bandai in 1998 to much critical acclaim, rival to Nintendo's popular handheld Game Boy video game system. Surprisngly, the portable unit took 10% of the marketplace. Featuring high resolution and gray scale graphics, games could be played on the horizontal or vertical. A color version is set to debut in December 2000 in Japan with a United States release to follow in 2001. Many big name developers Nintendo does not have signed on Game Boy do indeed develop for Wonderswan.