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Problem of the Week #36: Solution
11-15-2009
, 02:53 PM
Problem of the Week #36: Solution
Cash game. Black owns the cube. Black on move.
Should Black double? If he doubles, should White take or drop?
In Problem 36, Black took an early cube based on his ownership of White’s 2-point and the fact that White still had a checker left to escape. After that, the game developed almost perfectly for him. His deuce-point game caused White to bear in awkwardly, while Black’s front position came together and prevented White’s back checker from escaping. After White’s last roll (an awkward 4-4), Black finally has a clear advantage, although he still trails by 47 pips in the race. Is this the right time to double?
The answer is yes, and in fact White should give this game up. His pip count lead is largely an illusion, since Black is so close to completing a full prime and White isn’t even at the edge of the 5-prime yet. In addition, White’s game is on the verge of collapsing completely. Plenty of numbers leave additional shots next turn for White (6-5, 5-4, 6-2, 5-1, and 4-2 are the obvious ones), while doubles crunch his position further.
When your opponent’s position is overstretched and crumbling, you have to double before the blots appear; doubling later will just give him an easy pass.
Solution:
Black should double.
White should pass.
Part of doubling, however, is knowing how to play the positions that arise. Suppose you do double and White takes. How would you play these numbers for Black? (Scroll down a bit to see the answers.)
6-5?
6-4?
3-1?
4-3?
5-1?
6-5: Run with 23/12. Don’t break your prime by hitting on the 2-point. The prime is very powerful with White not yet at the edge, and hitting prevents White from moving.
6-4: Make the 2-point. The fact that you can point on White without giving up the prime makes this just slightly better than running.
3-1: Slot with 6/3 8/7. (6/5 instead of 8/7 is also good). This makes you a favorite to complete your 6-prime eventually, while allowing White to roll his disaster numbers like 6-5 and 5-4.
4-3: 8/4 6/3, for the same reason.
5-1: 8/3 6/5, for the same reason. Slotting is a key idea in this sort of position. Killing checkers by playing 6/1 8/7 makes the 6-prime too hard to complete.
Cash game. Black owns the cube. Black on move.
Should Black double? If he doubles, should White take or drop?
In Problem 36, Black took an early cube based on his ownership of White’s 2-point and the fact that White still had a checker left to escape. After that, the game developed almost perfectly for him. His deuce-point game caused White to bear in awkwardly, while Black’s front position came together and prevented White’s back checker from escaping. After White’s last roll (an awkward 4-4), Black finally has a clear advantage, although he still trails by 47 pips in the race. Is this the right time to double?
The answer is yes, and in fact White should give this game up. His pip count lead is largely an illusion, since Black is so close to completing a full prime and White isn’t even at the edge of the 5-prime yet. In addition, White’s game is on the verge of collapsing completely. Plenty of numbers leave additional shots next turn for White (6-5, 5-4, 6-2, 5-1, and 4-2 are the obvious ones), while doubles crunch his position further.
When your opponent’s position is overstretched and crumbling, you have to double before the blots appear; doubling later will just give him an easy pass.
Solution:
Black should double.
White should pass.
Part of doubling, however, is knowing how to play the positions that arise. Suppose you do double and White takes. How would you play these numbers for Black? (Scroll down a bit to see the answers.)
6-5?
6-4?
3-1?
4-3?
5-1?
6-5: Run with 23/12. Don’t break your prime by hitting on the 2-point. The prime is very powerful with White not yet at the edge, and hitting prevents White from moving.
6-4: Make the 2-point. The fact that you can point on White without giving up the prime makes this just slightly better than running.
3-1: Slot with 6/3 8/7. (6/5 instead of 8/7 is also good). This makes you a favorite to complete your 6-prime eventually, while allowing White to roll his disaster numbers like 6-5 and 5-4.
4-3: 8/4 6/3, for the same reason.
5-1: 8/3 6/5, for the same reason. Slotting is a key idea in this sort of position. Killing checkers by playing 6/1 8/7 makes the 6-prime too hard to complete.
