The WonderSwan was a handheld created by Bandai in 1999 to compete with Nintendo's Gameboy. In never took off outside Japan, but was a decent hit there.
It was actually designed by Gunpei Yokoi, the creator of the GameBoy.
It sported mostly a bunch of ports and some original Japanese games. Some notable games included Megaman and Bass.
A year later they put out the WonderSwan Color.
It didn't look half bad. They even got ports of Final Fantasy before any other handheld.