Having sufficiently hammered home the importance of a strong board and of building a strong prime, it is finally time to discuss how to obtain them. The best play might be obvious if you roll a point-making number like 31 or 42, but otherwise, there is no perfectly safe way to do it. How do we know what risks are worth making? The answer is to use builders.
A builder is a checker that is temporarily placed in our outfield with the hopes of being used to build our board in the future.1 In the opening game, while we still have 5 checkers on the midpoint, we should use any unconstructive roll to unstack it and generate some builders.
Consider a spare checker on the 9-pt, as below:
This position can arise after an opening 41, splitting our backcheckers and unstacking our midpoint (41: 24/23, 13/9). The blot on the 9-pt acts as a builder. It might feel scary to leave a blot within striking distance of our opponent’s backcheckers. It’s also so close to “home,” and will therefore cost us way more in the race if it’s hit. However, it’s well worth the risk, as the 9-pt builder is a powerful asset in the early game.
Let’s go through the numbers to convince ourselves of this fact. In addition to our usual inner-board-point-making numbers (31, 42, 53, and 64), the 9-pt builder contributes an additional 12 rolls (43, 54, and 65, which make the 5-, 4-, and 3-pts, respectively; 41, 52, and 63, which also make the 5-, 4-, and 3-pts.) It also allows for some constructive outer-board-point-making rolls, such as 21, 62, or any 4. 2 In total, this single builder is adding 18 good rolls, so long as it doesn’t get hit.
What are the odds it gets hit? The 9-pt builder is the closest indirect blot we can place to Gary’s backcheckers, and yet it can only be hit if he rolls a 62, 53, 44, or 22, adding up to 6 total bad rolls. This means that we are 3 times more likely to make a new point than we are to have a checker sent back. Well worth the risk!
This risk assessment can be done for all the outfield points between our 8-pt and Gary’s midpoint. Each of these points has slightly different qualities, and it’s worth dwelling on them for a moment. Consider the figure below:
This plot illustrates good point-making rolls above the horizontal line, and bad blot-hit rolls below it. As discussed above, it shows that the 9-pt builder provides 18 good rolls and 5 bad rolls. Builders on the further away 10- and 11-pts certainly offer less risk, but dramatically less of a reward as well, as they each provide half as many potential inner-board points. It’s notable that a 10-pt builder is at twice the risk of an 11-pt builder, but provides only a modest improvement in good rolls. This explains why it’s better to split away from it with an opening 32 (24/22, 13/11) and 43 (24/21, 13/9). That said, in all cases, the good always outweighs the bad when adding a builder, and the risk is proven to be worth it.3
- Technically, any spare checker that can be used to make an inner board point, such as the 3rd checker on the 8-pt, can act as a builder. There is no risk to having more spare checkers, so examining them doesn’t make for an interesting risk/reward lesson. ↩︎
- Actually, only 45 is left to contribute to this count. 41, 42, 43 and 46 have already been counted in other good rolls. ↩︎
- This plot also highlights the weakness of the 10-pt builder. Despite being closer to the 6- and 8-pts, it doesn’t contribute much to making inner-board points because of duplication; 31 is better used making the 5-pt than the 7-pt, and 42 is already useful for making the 5-pt. It’s basically just as good as the 11-pt, with twice the risk. This is why it’s always better to split away from the 10-pt when opening with a 23 or 43, for example. ↩︎
Next lesson: Three midpoint tips
Leave a Reply
You must be logged in to post a comment.