Backgammon is a race with a fight in the middle. Each side moves 15 checkers around the board with two dice, tries to hit the other side’s lone checkers, and races to bear every checker off first.
The board and the goal
The board has 24 narrow triangles called points, in four groups of six. Your home board is the bottom-right quarter; the computer’s is the top-right. A wooden bar divides the board in the middle, and the tray on the right holds checkers that have been borne off.
Your white checkers travel from the top right, along the top, down the left side and along the bottom into your home board. The computer’s dark checkers go the opposite way. The first side to bear off all 15 checkers wins. On a phone held upright the board is turned a quarter so it fills the screen.
Rolling and moving
The game starts with each side rolling one die. Whoever rolls higher moves first, using both dice.
Each die moves one checker that many points. One checker can use both dice in a row if the point it stops on in between is open.
You can land on an empty point, on your own checkers, or on a single opposing checker. A point with two or more opposing checkers is blocked.
Doubles are played four times: a 5 and 5 means four moves of 5.
You must use both dice if you can. If only one can be played, it must be the larger one when possible. If nothing can be played, the turn passes.
Hitting and the bar
A lone checker on a point is called a blot. Landing on an opposing blot hits it and sends it to the bar. A checker on the bar must come back in, into the opposing home board, before any other checker of that side may move, and it can only enter on an open point.
Making points (two or more checkers together) keeps your checkers safe and blocks the computer. Several points in a row form a prime that its checkers can’t jump past.
Bearing off and scoring
Once all 15 of your checkers are in your home board you can bear them off: a 1 takes a checker off the 1 point, a 6 off the 6 point.
A die higher than your highest checker bears off from your highest point; a lower die must be moved inside the board if it can.
Winning scores 1 point. If the loser hasn’t borne off any checkers it’s a gammon (2 points), or a backgammon (3 points) if the loser also has a checker on the bar or in the winner’s home board.
Choose a single game or a match to 3, 5 or 7 points, where gammons and backgammons count double and triple. There is no doubling cube.
Playing against the computer
Tap Roll (or the board) to roll. Yellow rings show which checkers can move.
Tap a checker to light up where it can go, then tap a lit spot or drag the checker there. Tap Done when your dice are played.
Undo takes back one checker at a time, or your whole last turn with the computer’s reply. The dice stay the same.
Easy makes loose plays, Normal plays the move its evaluation likes best, and Hard also looks ahead at every reply roll.