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Daily Quiz 9/12 + Ch-Ch-Ch-Ch-Changes
Posted By: adambulldog In Response To: Daily Quiz 9/12 + Ch-Ch-Ch-Ch-Changes (Daily Quiz)
Date: Monday, 12 September 2011, at 3:24 p.m.
Number 1
Salient features of the position:
• Blue leads by 27 pips. White has very little racing equity and will probably have to hit a shot to win. • White owns the cube but is unlikely to see anything like an efficient recube to 8. If white hits a shot he will cash. • Gammons are very low for both sides. Blue seems to be a little likelier to fluke into a gammon; White can use the gammon a little more than Blue due to the score. Gammons are not a big factor here. • Blue’s board is swiss cheese, so white can be bold in seeking his shot. Candidate plays: 11/7, 11/8; 7/4, 7/3, and 6/3/, 6/2. Breaking the six point can be discarded pretty quickly since the play busts up Blue’s board and doesn’t help much with the race.
Blue is faced with a choice between paying now and paying later. Paying now with 11/8 11/7 leaves 11 shots, all of which are immediately fatal unless Blue follows with a 16 from the bar. So Blue loses 30% of the games by paying now. Paying later with 7/4, 7/3 leaves open the delicious possibility of paying never. White is going to have to break his 16 point with most numbers next turn, allowing Blue to hit with twos, POH or P&P with most sixes, and clear the 11 point with all doubles. I think Blue wins more games and (a few) more gammons by paying later, so this must be the correct play.
Number 2
Salient features: • Blue is 16 pips behind in the race, 11 pips after the roll. He can win the game by hitting a shot and containing the hit checkers, or by winning the race. • Blue has a nice 4-pt blockade to contain any checkers he might pick up. • White has escaped both his back men. Blue has escaped neither of his own. • White has his best three-point board. At the moment he only has two spares but shortly he will have more. Anchoring soon is therefore a priority for Blue. • White is going to have a tough time finding a reasonable double in this game due to the score. Therefore Blue is likely going to get to stay in this game for a while. • White’s stack on his midpoint cries out for relief.
Blue’s first decision is going to involve the ace. Does Blue need to anchor right now on the 2-point? If so, then the play of the four probably doesn’t matter too much—either 8/4 or 13/9 is going to be right. I would play 8/4, slotting the important 4 point and keeping the spare on the mid. But anchoring on the deuce leads to a cramped game with little outfield coverage. Blue would much rather anchor on the three- or the seven-point. So the ace needs to be played 23/22. The next candidate play is 23/18, going immediately for the opponent’s bar point. If Blue can make this point he will have a nice game. But this play leaves a ton of shots, and allows White to unstack the midpoint productively. It also leaves Blue hanging out to dry if White rolls something like 54 or 11, pointing on the junior checker. I think 23/28 is too big. So the remaining candidates are 23/22, 13/9; and 23/22, 8/4. 13/9 has the benefit of keeping the inner board blot-free; while 8/4 puts the spare on the 8 point where it wants to go, slotting the next point that Blue wants to make, and also keeps a spare on the midpoint. I’m not sure about this, but I guess I choose 23/22, 8/4.
Number 3
Salient features:
• Blue is ahead by four pips. • White has a perfect home board at this point, but only four pips to spare before busting. White is stuck behind a 4-prime, which also contains the four best inner-board points. • White can win the game by hitting a shot or by racing. • White is going to have a nice bit of cube vig if he owns the cube. If he turns the game around, he likely will be contemplating a recube in a pure race or in a situation where he has an opponent’s man on the bar, a checker or two to finish bringing around and a partially crunched board. Either situation lends itself to a nice efficient recube. • Since white has all his checkers in his home board (apart from the two back men) he doesn’t get gammoned all that much. To have a good chance of winning a gammon Blue needs to close out both back men, which is harder than it may look. I reckon White loses maybe 10 percent gammons. • Blue has a blot on his ace point that may come back to bite him in an exchange of shots.
This looks like a cube due to Woolsey’s Law. I’m not sure it’s a take and it looks pretty scary for White. Most of the time a deuce-anchor game is a drop. I bet a lot of people will drop this.
I think I would probably drop this OTB, but now that I have been looking at it for ten minutes I think it’s a take. With good cube vig and ten percent gammons, White needs 26 -27% (25% minus 3.5% plus 5% equals 26.5%) to take this. I think he has that much via some combination of big doubles, fly shots, and miracle last ditch shots from the bar.
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