Why 8/5 6/5
8/5 6/5 makes your 5-point, the golden point, on the first move. It blocks the opponent’s back checkers, starts a prime, and turns every later hit into a threat to close them out.
The top five plays, rolled out
| # | Play | Equity | Behind the best | Wins | Gammons won · lost | 3-ply (rank) |
|---|---|---|---|---|---|---|
| 1 | 8/5 6/5 | +0.232 ±0.012 | — | 55.3% | 17.4% · 12.1% | +0.220 (#1) |
| 2 | 24/23 13/10 | +0.015 ±0.017 | 0.217 | 49.9% | 14.6% · 14.4% | −0.008 (#2) |
| 3 | 13/10 6/5 | +0.013 ±0.014 | 0.219 | 50.1% | 14.6% · 15.0% | −0.018 (#3) |
| 4 | 13/9 | −0.005 ±0.013 | 0.237 | 49.3% | 15.1% · 14.1% | −0.019 (#4) |
| 5 | 24/20 | −0.046 ±0.013 | 0.278 | 49.0% | 13.3% · 14.3% | −0.029 (#5) |
Equity is the average result in points per game for the player on roll, with the cube in play: each play rolled out 1,296 times, ± one standard error. Gammons include backgammons.
The alternatives
Nothing else comes close. Splitting with 24/23 13/10, slotting with 13/10 6/5 and bringing one checker down with 13/9 all finish at least 0.217 behind, the biggest gap of any opening roll.
All 16 legal plays, ranked at 3-ply
- 8/5 6/5 +0.220
- 24/23 13/10 −0.008
- 13/10 6/5 −0.018
- 13/9 −0.019
- 24/20 −0.029
- 24/23 24/21 −0.038
- 24/21 6/5 −0.040
- 24/23 8/5 −0.092
- 24/23 6/3 −0.121
- 24/21 8/7 −0.129
- 13/10 8/7 −0.130
- 8/4 −0.141
- 6/2 −0.160
- 6/5 6/3 −0.187
- 8/7 6/3 −0.225
- 8/7 8/5 −0.310
Questions about the 3-1 opening
What is the best opening move for 3-1 in backgammon?
8/5 6/5 (make the 5-point). In GNU Backgammon rollouts of the top five plays it scores +0.232, 0.217 ahead of the next play, 24/23 13/10.
Is 24/23 13/10 a mistake with an opening 3-1?
Yes. It gives up 0.217 points per game on average compared with 8/5 6/5, a large error for the first move of a game.
How was this 3-1 analysis made?
GNU Backgammon 1.07.001 ranked all 16 legal plays at 3-ply, then rolled out the best five, 1,296 games each, with the cube in play (money game, Jacoby off). GNU Backgammon 1.06.002, the version Boardgammon’s servers run, ranks the same five plays in the same order at 3-ply.
How these numbers were made
GNU Backgammon 1.07.001 ranked every legal play at 3-ply with the cube in play (money game, Jacoby off, no beavers), then rolled out the best five: 1,296 games each, with variance reduction and quasi-random dice. GNU Backgammon 1.06.002, the version Boardgammon’s servers run, ranks the same five plays in the same order at 3-ply. Evaluated on 2026-10-20. The same engine analyses every finished online game on Boardgammon: see how that compares. New to the numbers? Read what equity and a rollout are.
Terms on this page: Golden point, Prime, Blitz, Point. Next in the strategy guides: cube theory.