Game 3, move 18: Forum 5-4

[diane]

Forum (blue) to move 5-4.   

MztgBgPbMoMZAA:QYmyACAAAAAA

[vikingblood80]

Spoiler

nothing special...clear the 8, wait rkb to get in trouble

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[lewscannon]

Spoiler

Doesn't seem like much choice here but to be patient, move the 8-4 8-3 and wait for rkb to open up. Diane, please load the 6-6 for our next roll if we don't get a hitting opportunity here.

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[ah_clem]

Spoiler

  Decision by process of elimination:

Candidate moves (with good but bad commentary):

15/6 - begins to clear the trailing point, but leaves a double shot

13/4 - begins to clear the midpoint and makes a 5th home board point, but leaves a double shot.

13/8 13/9 - clears the midpoint, but leaves a single shot

8/3 8/4 - leaves no blots and makes a 5th home board point, but abandons a key point that will be helpful in clearing the two trailing points.

6/1 6/2 - leaves no blots, but burries checkers and destroys our four point board.

(The other two are so bad I'd only  consider them if I were "helping" rkb. )

6/1 6/2 is anti-positional, so I'm going to eliminate that.

Leaving a double shot against a four point board invites disaster, so 15/6 and 13/4 are out as well.

That leaves the safe play 8/4 8/3 and the bolder play 13/8 13/9.  Pay now or pay later?  If rkb didn't have a formidible board, I'd say pay now.  But he does, and I'm not feeling lucky.  Abandoning the 8 point is not at all what I want to do, but safe play plus making a 5th homeboard point tips the balance in it's favor. 

8/4 8/3 

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[KDP]

Spoiler

not a great roll, but i have to go with 8-3. 8-4 as it strengthens our home board, and clears a point.  hopefully we'll get a double soon to bring our other 4 checkers home.

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[ah_clem]

This is looking very nextish....

[diane]

It would be nice to hear from the person who picked the one different move, but it does seem nextish - if no new views appear in the next couple of hours, I will move it along.

[ah_clem]

It would be nice to hear from the person who picked the one different move...

Spoiler

I'm not the one who voted for it, but:

It's a credible move, and may even be best.  Our problem is to exploit our racing lead and get our men home without being hit.  The big thing 13/8 13/9 has going for it is that it keeps our outfield checkers in communication (ie within 6 points) making it easier to clear them, where the popular move opens up a gap of 7, breaking communication. The cost of 13/8 13/9 , of course, is leaving a blot now - but if we don't get hit, we're in much better shape than with the other move.  

It's a pay now or pay later decision, and when trying to decide these I like to consider the liklihood of 'not pay at all' i.e. if rkb leaves a blot first we don't have to pay.  That liklihood and making the four point pushed me in the direction of clearing the 8.

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[lewscannon]

Spoiler

Don't forget that rkb is in the same boat as us here. He may open up for a shot before we do.

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[ah_clem]

gnubg results:

Spoiler

Evaluation has the bolder play as slightly better

    1. Cubeful 2-ply    13/9 13/8                    Eq.:  +0.324
       0.638 0.119 0.001 - 0.362 0.072 0.001
    2. Cubeful 2-ply    8/4 8/3                      Eq.:  +0.311 ( -0.013)
       0.620 0.143 0.001 - 0.380 0.088 0.001
    3. Cubeful 2-ply    13/4                         Eq.:  +0.294 ( -0.030)
       0.608 0.151 0.002 - 0.392 0.093 0.002
    4. Cubeful 2-ply    15/6                         Eq.:  +0.105 ( -0.219)
       0.550 0.121 0.002 - 0.450 0.129 0.002
          2-ply cubeful prune [expert]

Rollout says clear the eight point, but the other play is not too far behind:

    1. Rollout          8/4 8/3                      Eq.:  +0.283
       0.612 0.131 0.002 - 0.388 0.084 0.001 CL  +0.346 CF  +0.283
      [0.001 0.001 0.000 - 0.001 0.001 0.000 CL   0.004 CF   0.004]

    2. Rollout          13/9 13/8                    Eq.:  +0.267 ( -0.016)
       0.622 0.102 0.002 - 0.378 0.072 0.002 CL  +0.331 CF  +0.267
      [0.001 0.001 0.000 - 0.001 0.001 0.000 CL   0.004 CF   0.004]

    3. Rollout          13/4                         Eq.:  +0.240 ( -0.043)
       0.594 0.131 0.002 - 0.406 0.090 0.002 CL  +0.305 CF  +0.240
      [0.001 0.001 0.000 - 0.001 0.001 0.000 CL   0.004 CF   0.003]
        Truncated cubeful rollout (depth 11) with var.redn.
        1296 games, Mersenne Twister dice gen. with seed 866608274 and quasi-random dice
        Play: 0-ply cubeful prune [expert]
        Cube: 0-ply cubeful prune [expert]

Interestingly, running from the 13 is not so bad either...

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[roadkillbooks]

These are rollouts:

I get that if the score was 2-0 the other way (forum winning), it would be slightly better to make the 13/8,13/9 "bold" play.  So how about money play and 0-0.....

At money play..centered cube I get... the safe play being 0.045 worse than the bold.

if i had the cube in money play.....  bold play wins by .02

if forum had cube in money play...   it's bold by .008
-
at 0-0

foum cube.....bold + 02
center cube ....bold by .059
roadkill cube.....bold by .012

So bold is best in most situations except this one.  Pretty surprising it was such a lopsided vote I guess.  The general logic in holding games is to play safe if you can make your board better.  And then in many situations it's even break your board if the opponent have a good chance of leaving a shot before you.  The "safe" makes another point and I was at risk to leave a shot.  I would have gone for safe also...probably in most of the other options as well.