At first glance, the games do not bear much resemblance, but I think it is interesting to note that in Japanese chess, just as in Go, you are allowed to place your pieces anywhere you like on the board if it's your move, provided you have a collection of pieces by the side of the board that you have taken in the course of the game.

Basically allowed to drop pieces like stones instead of moving any piece already on the board.

There's playok.com and 81 Dojo to play on the Internet, should work fine on mobile devices.