Planning over speed — read the minefield, flip the board, fence off territory, play a real game of Go. Free, in your browser.
Strategy games reward the move you make three turns from now. Read the field in Minesweeper, turn the board to your colour in Reversi, claim squares in Dots & Boxes, or play a real game of Go on a 9×9 board.
There is no clock forcing your hand, so these are slow, satisfying games you can put down mid-match and come back to. The computer opponents scale from a gentle warm-up to a genuinely tough match.
Set a board, send the link, and see whether a friend can solve it more cleanly than you did.