Why 24/13
24/13 runs one back checker all the way to safety on your midpoint. You lead the race from the first move, and only one back checker is left to escape.
The top five plays, rolled out
| # | Play | Equity | Behind the best | Wins | Gammons won · lost | 3-ply (rank) |
|---|---|---|---|---|---|---|
| 1 | 24/13 | +0.111 ±0.011 | — | 53.0% | 12.7% · 12.6% | +0.096 (#1) |
| 2 | 24/18 13/8 | +0.038 ±0.014 | 0.073 | 51.3% | 13.9% · 13.9% | +0.036 (#2) |
| 3 | 13/8 13/7 | −0.044 ±0.019 | 0.154 | 48.2% | 14.6% · 14.7% | −0.054 (#3) |
| 4 | 13/2 | −0.118 ±0.014 | 0.228 | 46.9% | 14.1% · 16.6% | −0.121 (#4) |
| 5 | 24/18 8/3 | −0.189 ±0.013 | 0.299 | 46.2% | 12.2% · 17.5% | −0.158 (#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
24/18 13/8, the main alternative, is 0.073 behind, and bringing two builders down with 13/8 13/7 is worse still.
All 7 legal plays, ranked at 3-ply
- 24/13 +0.096
- 24/18 13/8 +0.036
- 13/8 13/7 −0.054
- 13/2 −0.121
- 24/18 8/3 −0.158
- 13/7 8/3 −0.205
- 8/3 8/2 −0.378
Questions about the 6-5 opening
What is the best opening move for 6-5 in backgammon?
24/13 (run with the lover’s leap). In GNU Backgammon rollouts of the top five plays it scores +0.111, 0.073 ahead of the next play, 24/18 13/8.
Is 24/18 13/8 a mistake with an opening 6-5?
A small one. It gives up 0.073 points per game on average compared with 24/13.
How was this 6-5 analysis made?
GNU Backgammon 1.07.001 ranked all 7 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: Lover’s leap, Midpoint, Running game, Race. Next in the strategy guides: cube theory.