the dorbel daily

Saturday, 16 July 2011

"A Reader Asks.......Part 2"

As a follow-up to the last post, I now have the whole match from which that position came and here is the same game three rolls earlier. Thank you to Warner Bouzek who sent it to me. Feel free to do the same if you have something interesting.

Position ID: /10AABiz3QYQAg

Here is an excellent opportunity for a trap play. The best play is 20/18, 16/14, 7/3. Note how the moves to 18 and 14 cover every point in the outfield, ensuring a direct shot or its eqivalent after every five or six for White. Even if White rolls 5-1 or 5-2 and picks up her inboard blot, Black will still have 17 shots at the White checker on the deuce point including 6-6 and 4-4 from the 14pt. Even when White rolls 5-5 and covers the blot, Black still has 15 shots from the bar.
Some players will jib at the risk involved, unwilling to let White out in order to pursue a closeout and a gammon. Experts won't, because they have been here before. If you instinctively make the "safe" play here, then you won't know what happens after the trap play and you'll never learn to play it. You can avoid this by playing it fifty times and comparing the results with fifty rounds of your safe play. You'll soon grow to love the trap!

Another reader writes, "How early in the game should I think about doubling?" The answer is that you should always be alert to a double opportunity, as they can occur from the second roll onwards. Here are four examples. Take a look at them and let us know in the comments section what you would do with these. In each case Black is on roll. I want to know the correct cube action for both sides.

Position One

It's a nine point match, the first game and White opened with a 5-2, played 24/22, 13/8 and Black pounded her with 5-5. White danced. Should Black double and if he does, should White take?
Position 2

Again, nine point match, White rolled 6-2 and played 24/18, 13/11 and again, Black rolled 5-5 and again poor old White danced. Should Black double and should White take if he does?

Position 3

This is from a 5 point match and White leads 3-1. Black started with a 3-1 and White rolled a 6-3, correctly played 24/15. Should Black double and should White take if he does?

Position 4

The same position but now White leads 4-3 to 5 and it is post-Crawford. Should Black double and if he does, should White take?

Some of my expert readers will look at these and say, "Well these are too easy". However, they are all from live matches, all involving players at the top of the tree and all drew mistakes from one side or the other! See if you can do better please.

Until tomorrow, which may even be tomorrow, enjoy the game!


ah_clem said...

1) I play mostly 5 or 7 pointers, and I'd definitely double in the first game with this position. For short matches, get some gammon chances and ship the cube. Here, it's a longer match, but I'd still double. Maybe I'm wrong, but Black has Position Race and Threats (PRT), so it must be good enough to double. Is it too good? Well, black still has lots of work to do extricating his runners, and there's only 8 checkers in the zone, so I don't think it's too good.

As for the take, being behind in PRT is usually a drop, but I think White can squeeze out a take - if she anchors it's a new ballgame, and the chances of anchoring are high. D/T

2) Again, advantage in PRT, but White is a bit better off. Another D/T but this time the take is clearer.

3) When your opponent is 2-away her take point is rather high, so you have to be more aggressive with the cube lest you lose your market. And with you at 4-away a doubled gammon wins the match, so this score calls for an itchy cube finger. I say ship it. The take seems clear, as the game has barely started. D/T

4) Mandatory Double, Free Drop. D/P An easy one if you know those concepts. (There's an exception if black is too-good, but I don't think that's the case here.)

moonshadow said...

I was just wishing for some cube action problems like this and here they are!

My replies, for bettor or for worse, are as follows and I await to see dorbel's response, either to affirm my reasoning or either to correct the error of my ways.

1) double, take

2) double, drop

3) double, take

4) double, drop

Timothy Chow said...

1. This should be a pass even without any extra White checkers to pick up. D/P.

2. If White's outfield blot were still on the midpoint then I think this would be on the take/drop borderline. The outfield blot probably makes White's position slightly worse, so D/P for me.

3. At 4-away/2-away one barely needs an excuse to double. Making a strong home-board point and getting a weak response is enough. D/T.

4. White has a free drop so the drop is clear; the only question is whether it's too good. I remember that 31P-62S is slightly too good, and this looks pretty similar. It seems unlikely that White will have a take next turn so I'd play on. TG/P. By the way, do bot rollouts support 31P-63R rather than 31P-63S at this score?