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On his blog, Robertie publishes set and equipment reviews, creates quiz contests and provides free lessons. He would be remiss not to include his Robertie’s Rules! He also educates readers of the Gammon Press blog on the history of the game, offers backgammon instruction and more.

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Early Doubles

Cash game, center cube.

Should White double? If he doubles, should Black take or drop?

In the last post we talked about the importance of cube benchmark positions — positions where one of the cube decisions (either doubling or taking) was perfectly marginal, while the other was completely clear. Learning typical benchmark positions gives us the ability to analyze a wide variety of related positions over the board with unusual accuracy.

This position shows us another type of useful benchmark. We’re currently just four moves into the game. The opening sequence was

White: 5-3, making the 3-point.
Black: 4-3, bringing down two builders.
White: 6-2, hitting.
Black: 6-3, dancing.

With Black on the bar and White clearly having the upper hand, White now contemplates a double. Considering Sylvester’s three criteria for offering an initial double, here’s how White stands:

Race: solid edge for White. His hit and Black’s fan leaves White up 25 pips, 151 to 176.

Threats: small edge for White. He’s threatening to hit Black’s other blot, but White’s weak board means this is really just a threat to gain a little more ground in the race.

Position: Small but solid edge for White. He has a 2-point board, while Black’s board is undeveloped. White’s extra point, however, is just the 3-point, and there’s no prime in the immediate future. White has almost escaped one of his back checkers, another plus.

To summarize, White has a sizeable edge only in the race, while his other edges are small. Rollouts show that this is a small but correct double, which of course means that the take is very clear. White’s problem is simply that a big lead in the race isn’t as significant as one might think if the inner board is weak. The most likely sequences in that case are ones in which Black easily makes a good anchor or exchanges of hits occur; either of these scenarios minimizes White’s racing lead.

If you were at all tempted to drop this position as Black, just remember that the combination of a weak board, few builders, and an anchor for Black almost always guarantees an easy take. That’s the case here.

Once you know the value of this position in a cash game, you can easily make some practical adjustments for tournament play. If White were trailing in a match, this would be an easy double. If White were the better player, it would also be an easy double, since this will be a long game and White should expect to outplay Black in the later maneuvering.

Benchmark Doubling Positions

Cash game, center cube.

Should White double? If he doubles, should Black take or drop?

A key idea in understanding the proper use of the doubling cube on a practical level is that of the “benchmark” position. A benchmark cube situation is a position where one of the decisions (doubling or taking) is a toss-up, while the other is completely clear. Properly understanding a benchmark position is very useful since it unlocks the key to many related positions. Just compare your actual position to the benchmark, spot what the relevant differences, and you should be able to make a good cube decision over the board. Better players are aware of hundreds of good benchmarks, so they can make their over-the-board decisions quickly and accurately.

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Action Doubles

Cash game, center cube.

Should White double? If he doubles, should Black take or drop?

This position shows a pretty interesting middle game position. Both sides have an anchor, and some points scattered around. White, however, is on roll and shooting at a bunch of blots. He has a total of 27 hits: all sixes, all fives, 4-3, 4-1. 3-2, and 3-3. That’s a lot of hits, so he’s naturally thinking about doubling, and Black is probably worrying whether or not he’ll have a take if White ships the cube.

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Doubling Blitzes

Cash game, center cube.


Cash game, center cube.

Should White double? If he doubles, should Black take or drop?

We’re in the early stages of the game and White is contemplating a double. Some time ago Joe Sylvester developed a rule for evaluating early doubles. Sylvester advocated looking at three aspects of the position:

(1) Positional advantage (board strength, primes)

(2) The race

(3) Threats

A solid lead in two out of three areas usually translates into a good initial double. A lead in all three guarantees a good double and brings the take into question. Let’s look at all three features of the position in light of Sylvester’s Law and see what we get.

(1) Positional advantage. No one really has a priming structure yet. White has one more home board point and one more outfield point, but Black has his 5-point. Slight edge to White.

(2) Race. Huge edge for White, who leads in the pip count, 118 to 152.

(3) Threats. Another big edge for White, who has five crushing doubles (1-1, 2-2, 3-3, 4-4, and 6-6) plus another six rolls that make the 4-point (6-4, 6-2, 4-2). In addition, White can at least hit loose with most of his other numbers.

A big edge in two out of three categories certainly implies White can double. At the same time, Black has a pretty easy take. White only has three really crushing numbers (2-2, 4-4, and 6-6). Everything else gives Black a chance to anchor on his next turn, with a long game in progress. And of course, Black does have his 5-point, which is a big asset in his favor.