Handheld console produced in Japan and developed by Gunpei Yoko (also developer of the Nintendo Game Boy).

Later replaced by the Wonder Swan Color which was released on December 9, 2000.

Tech specs:
CPU: 16-bit NEC V30 MZ processor at 3.072 MHz
Internal memory: Built-in EEPROM and 1Kbit RAM for backing up game data.
Screen resolution: 224 x 144px
Color: 8-shade monochrome