Play backgammon online, around a star

Orbit & Eclipse is a free online backgammon game with a twist: the board is a ring of 24 glowing lanes orbiting a star. Your moons race around it toward your home, a moon that gets hit falls into the star and has to fight its way back out, and you bear off through a warp gate.

Play against a computer that learned backgammon by playing itself 150,000 times, challenge a friend with a link, climb the ranks from Cadet to Star Admiral, and unlock new star systems and moons. There's a fresh daily puzzle every day. Nothing to download, no account, works on phones and computers.

How to play backgammon

1. Each player has 15 checkers. You move yours around the board toward your home, the six points next to the warp gate, then bear them off. The first player to bear off all 15 wins.
2. Roll two dice and move one checker by each number, or one checker by both. Doubles let you move that number four times. You must use both dice if you can.
3. You can land on any point that has fewer than two of your opponent's checkers. Landing on a single opposing checker (a "blot") hits it and sends it to the bar, here the star in the middle.
4. A checker on the bar must re-enter in your opponent's home before you can move anything else.
5. Once all your checkers are home, you can bear them off with exact rolls, or with a higher roll from your furthest-back point.

Scoring, doubling and matches

• A normal win is worth 1 point. If your opponent hasn't borne off any checkers it's a gammon (2 points), and if they still have a checker on the bar or in your home it's a backgammon (3 points).
• In matches to 3 or 5 points you can offer to double the stakes with the doubling cube before rolling. Your opponent either takes (and owns the cube) or drops and loses the current value.
• The Crawford rule applies: in the game right after a player gets one point from winning the match, nobody can double.

Tips

• Make points, especially your 5-point and bar point. Two checkers on a point make it safe and block your opponent.
• Count shots before leaving a blot. A blot six or fewer pips in front of an enemy checker is in danger.
• Build a prime. Six points in a row can't be jumped.
• Use “Expert’s pick” to see what the computer would play before you move.

Questions

Is Orbit & Eclipse free?

Yes, free with no ads and no sign-up. Your rank and unlocks are saved in your browser.

How strong is the computer?

Easy and Normal play heuristically. Expert uses a neural network trained by self-play, the same idea as the classic TD-Gammon program, and it uses the doubling cube.

What is the daily puzzle?

Every day everyone gets the same position and roll. Find the best play to earn three stars and keep your streak alive.

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