Side Pocket is a pool-style game for the WonderSwan. The WonderSwan version likely offered simplified controls adapted for the handheld's form factor, and the gameplay likely focused on the precision of aiming and shot power. The game likely aimed to capture the feeling of playing pool in a compact and easily portable format. The 'J' indicates a Japanese language release.  Details on the development team and publishing information require deeper research into Japanese gaming archives. '[M]' could indicate a mature rating, and '[!]' might signify a rare or limited print run. 

Side Pocket (J) [M][!]

Shanghai Pocket (J) [M]