Game 4, move 41 Blitzxz and 42 Forum : Forum 5-4

[diane]

Blitzxz danced again with 5-2, so forum, blue, to move 5-4

There is one obvious move..but you might not want to do that 

H98AAFi27aAEEA:QYmyACAACAAA

[diane]

Spoiler

I want to be controversial here, I can't see any value to making that 7.  I would rather move my checkers around, creating opportunities to get either more hits or the ace point back.  He already has a weak board, so I would not be worried about being hit back, and a gammon is so much more attractive here.

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[ah_clem]

Spoiler

I want to be controversial here, I can't see any value to making that 7.  I would rather move my checkers around, creating opportunities to get either more hits or the ace point back.  He already has a weak board, so I would not be worried about being hit back, and a gammon is so much more attractive here.

I look at it this way: with three of our opponent's checkers way back, our gammon chances are pretty good.  Making the 7 point guarantees that they'll remain there for quite a while.  OTOH, if we leave an escape hatch, any six (after entering) gives him a chance to reduce his pipcount and possibly avoid a gammon. So, my take is that making the 7 increases our gammon chance.

Moreover, by making a prime, we can afford to leave the runner where it is without fear of losing and maybe pick up another checker.  This is a longshot, but stranger things have happened. 

As for "move my checkers around, creating opportunities to get either more hits or the ace point back" I don't see what we're going to hit.  An escapee? He's already on the bar, what's the point of letting him escape only to whack him again - granted, that's what my cats do with mice, but they're terrible backgammon players.  And getting the ace point back is of limited utility if we've broken contact, and we have too little timing to let him escape and maintain contact.

Some moves are hard.  Some moves are easy.  This one is easy. Make the prime.   Let's not overthink things.

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[dorbel]

Spoiler

I think it's right to make the bar. We'll be happy to have it if he enters soon and it shouldn't be too dangerous to break it later with his board looking like a train wreck. One thing we must do though is stay back on the 23pt to try and pick up another checker if he enters 1-2, 1-3, 1-4. The spread out variation, 14/9, 12/8 works pretty well if he enters 1-6 of course, but only if we actually hit our triple shot!
What is this "getting the ace point back"? Means nothing to me.

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[diane]

Spoiler

What is this "getting the ace point back"? Means nothing to me.

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Spoiler

I am not sure what is complicated abut that statement, I am not being deliberately cryptic.  He has a point on the forums ace point..this can make bear off more tricky than if he wasnt there...If we allow the escape route, he may be forced to move off it - and we can claim it, then clean up any checkers moved and pop them on the bar on the way back..simple really.  I would be prepared to try for this slightly more risky game with potential for higher rewards - because he doesnt have much of a board.  If he had a good board and it served him to sit on the bar and wait, then I would make the bar point and hold him where he is and force the break up of his board should he enter.

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[dorbel]

Oh I see. It's going to be some time before we get something to pot at with that method, but you are right that making the bar point isn't particularly valuable here or for that matter particularly dangerous! If my partner in a doubles preferred not to make it I wouldn't argue strongly against it, as long as he didn't want to leave the 23 point on this roll. In these situations where it isn't clear which course is best, I like to take a solid asset and see what happens next, rather like clem in this case, but your plan may well be best.

[ah_clem]

rollout

Spoiler

Making the bar point isn't the prize I thought it was, but it's still best by a comfortable margin.



    1. Rollout          12/7 11/7                    Eq.:  +1.667
       0.966 0.378 0.122 - 0.034 0.000 0.000 CL  +1.674 CF  +1.667
      [0.001 0.002 0.006 - 0.001 0.000 0.000 CL   0.006 CF   0.006]

    2. Rollout          14/10 12/7                   Eq.:  +1.628 ( -0.039)
       0.956 0.371 0.115 - 0.044 0.002 0.000 CL  +1.637 CF  +1.628
      [0.001 0.003 0.006 - 0.001 0.000 0.000 CL   0.006 CF   0.006]

    3. Rollout          14/9 11/7                    Eq.:  +1.622 ( -0.045)
       0.954 0.370 0.115 - 0.046 0.003 0.000 CL  +1.633 CF  +1.622
      [0.001 0.003 0.006 - 0.001 0.000 0.000 CL   0.006 CF   0.006]

    4. Rollout          14/9 12/8                    Eq.:  +1.614 ( -0.053)
       0.957 0.361 0.104 - 0.043 0.001 0.000 CL  +1.622 CF  +1.614
      [0.001 0.003 0.006 - 0.001 0.000 0.000 CL   0.006 CF   0.006]

    5. Rollout          14/5                         Eq.:  +1.589 ( -0.078)
       0.954 0.354 0.105 - 0.046 0.001 0.000 CL  +1.601 CF  +1.589
      [0.001 0.003 0.006 - 0.001 0.000 0.000 CL   0.006 CF   0.006]
        Full cubeful rollout with var.redn.
        1296 games, Mersenne Twister dice gen. with seed 848583725 and quasi-random dice
        Play: 0-ply cubeful prune [expert]
        Cube: 0-ply cubeful prune [expert]

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