Meet the Mephisto Mobil: a modular chess computer from the 1980s that can give you a good game anywhere. It has a foldable tiny magnetic chessboard, so you can follow the moves. You can use this with wide variety of Mephisto chess computer modules. You can power it with an adapter or 9v battery.
These modular chess computers are pretty rare but they show up on sites like eBay once in a while.