We continue our series on cluster counting by learning a few more common clusters for checkers near and around our home board.
4. The deck
Continuing with our series of named cluster positions, we have the deck. This one is a prime that extends from the 5-pt to the 8-pt. It’s aptly named, since not only does its low, flat structure resemble a deck (7-8 pts) that extends beyond just your house (5-6 pts), but it contains 52 pips, just like a deck of cards. This one is kind of an earworm, where once you hear about it it’s unforgettable!
A common cluster worth remembering is the just exterior part of the deck: if we have both our 7- and 8-pts made, those checkers add up to an easy 30 pips:
Another related cluster that appears frequently is the one below, including 5 checkers on the 6-pt. It’s the cluster that arises when you make the bar with an opening 61 roll:
This cluster is worth 60 pips.
5. Primes
We already tackled 5-primes in part 1 of this series. There turns out to be a great trick that works on any double-decker prime: you add the front point and the rear point and you multiply by the length of the prime.
For example, consider the deck, which is just a 4-prime:
The length of the prime is 4. It starts on the 5-pt and extends to the 8-pt. Using the formula (5 + 8) × 4 gives us 52, as expected for the deck.
Another example: the 7-prime below extends from the 2-pt to the 8-pt:
(2 + 8) × 7 = 70 pips. We can double-check this tally by treating it like a 5-prime centered around the 4-pt (40 pips) and the 7-8-pt exterior deck (30 pips).
Next lesson: Cluster counting 3: outfield points
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