The first type of doubling position we will study is a straight racing position. You’ve **broken contact** with your opponent and now you’re both hoping to roll well and win outright. You can probably tell if you are leading just by looking at the board, but do you have enough to offer your opponent the doubling cube?

In the position below, you have 87 pips remaining, whereas Gary has 118, for a lead of 31 pips. Should you double yet? Should he take?

The analysis tells us that you have a 97% win chance. You certainly have a double, but Gary would have to be crazy to take it. He will have to drop it. (D/P)

On the other hand, below, you and Gary have 88 and 97 pips, respectively, for a difference of just 9 pips. Here, your win chances are 75%. You are exactly within the doubling window, and Gary should take. (D/T)

How do you figure this out over the board? In pure racing positions like this, where none of the checkers have “wastage” (that is, they aren’t lined up on the 1 -pts or 2-pts and you don’t have large gaps on the 4-pts or 5-pts) you can use a simple racing formula: it’s a **D/T if your opponent has a pip count that is 8 – 12%** higher than yours.

Calculating 8% or 12% over the board is no easy feat, but we can take a shortcut: just **divide your pip count by 10 and add or subtract 2**.

Let’s see how to apply this formula to the positions above. In the first position:

- You had 87 pips.
- 10% of 87 is 8.7.
- 8.7 – 2 = 6.7. This roughly corresponds to 8%.
- 8.7 + 2 = 10.7, corresponding to 12%.
- The doubling window is therefore for a pip difference between 6.7 and 10.7.
- (Note that the “real” 8 – 12% window is between and 7.0 and 10.4 pips. Close enough!)
- Finally, the difference, 31, is larger than 6.7, so you should double. However, it is also larger than 10.7, so Gary should
**not**take. The deficit is well beyond the doubling window.

In the second position:

- You had 88 pips.
- 10% of 88 is 8.8.
- 8.8 – 2 = 6.8; 8.8 + 2 = 10.8. Therefore, the doubling window is between 6.8 and 10.8.
- The pip difference, 9, is between 6.8 and 10.8, so you should double and Gary should take.

That’s all there is to it! The only catch is that you need to know the pip counts. Online it’s usually given to you, but in real life, you will need to learn how to figure it out. We will eventually learn different methods to count pips.

##### Further reading:

- A lecture by GM Zdenek Ziska on cubing, where he discusses racing positions.

Next lesson: Doubling in N-roll positions

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