How to play

Acey-Deucey is backgammon's cousin: everyone starts off the board. You are White. Your checkers enter from the tray at the top right onto points 19 to 24 (24 minus the die, plus one), then travel down the board toward point 1 and off. The computer player is Black and goes the other way. In this version every checker must be entered before any checker may move on.

Tap Roll, tap the tray, bar, or point you want to move from, then tap the landing point. A checker alone on a point is a blot; land on an opponent's blot and it goes to the bar and must re-enter. Once all fifteen of your checkers are in points 1 to 6 you can bear off by tapping the tray at the lower right. First to bear off all fifteen wins.

Acey-deucey! A roll of 1 and 2 is special: you play the 1 and the 2, then any double of your choosing four times, then you roll again. The computer player always takes sixes.

The Oracle

The Oracle is an optional advisor for you alone. Tap 🔮 to open it. Every time you roll, it lists every legal play for that roll, best first, and explains its top pick in plain words. On an acey-deucey roll it also ranks the six doubles before you choose. Tap any option to see it on the board: purple marks the checker to move, gold marks where it lands (numbered in order), and red marks an opponent checker that would be hit. It keeps advising each turn until you close it; Consult again re-runs it. It never helps the computer player, which keeps its own way of playing.

How it thinks

The Oracle uses a "minimax" search: for each of your plays it imagines what happens next and assumes the opponent always answers with their best play. Because dice are involved, it can't know the opponent's roll, so it tries all 21 possible rolls, works out the opponent's best reply to each, and averages the results, weighting rolls by how likely they are. An opponent's 1-2 is counted as 1, 2 and four sixes, which is exactly what the computer player plays. If time runs short it looks at a sample of rolls instead and says so in the fine print.

How far it looks ahead follows the level you choose: level 1 judges your play on its own, level 2 (the default) adds the opponent's averaged reply, level 3 adds your own next roll as well. Deeper looks take longer and may not finish within the time limit; when that happens the Oracle keeps the deepest level it completed.

It scores a position by five things: the pip count (how far each side still has to travel — checkers still in the tray or on the bar count 25), blots left and how likely they are to be hit, points held (home-board points count extra), opponent checkers on the bar, and checkers borne off. A finished game counts as an exact win or loss. Tags are green for a certain win, red for a certain loss, and amber for a judgement — "Ahead 12 — safe" means you would lead by 12 pips with nothing left to hit.