Goal. Have the lowest total score after all rounds. Your score each round is the pips left in your hand. The double-blank counts 50.

Rounds. Round 1 starts with the highest double (the 9-9 in a double-9 set), round 2 with the next lower double, and so on down to the 0-0. Whoever holds that round's double sets it in the center. If nobody holds it, players draw in turn until it turns up.

The starting double. It must get all of its lines (4 or 6, as chosen at setup) before anyone may play anywhere else.

The chicken foot. When anyone plays a double out on a line, it must get 3 dominoes fanned off its end — the chicken foot — before anyone may play anywhere else.

Can't play? Draw one domino from the boneyard. If it fits, play it. If not, you pass. If the boneyard is empty, you pass.

End of a round. A round ends when a player plays their last domino, or when nobody can play.

Your turn. Dominoes that fit are raised and outlined in gold. Tap one. If it fits only one place, it is played at once. If it fits more than one place, gold lettered tags (A, B, C…) appear on the table and as buttons — tap the one you want.

The table. The camera glides to wherever play happens. Drag to look around, pinch or scroll to zoom. Follow Play turns the gliding camera on and off, and Whole Table shows everything. Tap the overview map in the corner to jump to any spot. Every open end carries a small number tag so you can read the table at a glance. Dashed outlines show spots that still must be filled.

The Oracle. On your turn, The Oracle plays out thousands of possible rounds for each move you could make, and ranks your moves by the pips you are likely to be left holding. It also uses what the other players have shown: whenever Slim, Tex or Dusty draws or passes, that proves they had nothing matching the open ends at that moment.