In the
linked document, I have posted 5 positions that arose during the same endgame. In the first position, Blue has borne off all but two checkers and has a 95% chance of winning. In the second position, Blue’s winning chance has fallen to 87% (because Blue no longer has a point?) In Positions 3 - 5, Blue’s winning chance has fallen to the 46% - 55% range, presumably because White has built a prime.
I have a number of somewhat general questions about these positions:
Q1: In the first position, what should each player’s game plan be? Of course, Blue wants to get home — does this usually require making a point or trying to run one checker home by itself? Presumably, White wants to build a prime — but does it matter much where White builds her prime?
Q2: By the time we reach Position 3, how do the game plans change? I assume that White should break her 6-prime to force Blue to break her point. But which point in the 6-prime should she break?
Q3: When we move from Position 4 to 5, Blue’s win chance goes from 46% to 55%. Why is this? The positions look very similar to me.
I also have some questions about XG’s recommendations (which strike me as very strange):
Q4: In Position 2, White’s play makes a 3 prime (by making the 10 point) whereas XG breaks the prime entirely. What is XG doing here?
Q5: In Position 3, I would have played Bar/19 9/7. The idea is to break the prime and so force Blue to play 1s (aiming for the close out). However, this doesn’t even show up in XG’s list so must be a huge blunder. What’s wrong with my play? In addition, why is XG’s play so much better than the play White chose (Bar/17)?
Q6: In Position 4, both White and XG played the same 6 (from the 19 point). However, apparently it makes a huge difference how you play the 1. Why?
Q7: In Position 5, I would have again broken the 6-prime, e.g. by playing 9/6 7/6. Again, however, this is a huge blunder. So what I am missing? And what was my opponent White missing when they made their play?
I know this is a lot of questions — so feel free just to answer one or two of them! And thanks in advance for any ideas or suggestions.