Position # 35

[PersianLord]

Position information:

Pip-count: Red 104-129 White
Score:       Red     0-0     White
Match:                   5-pointer

Red to play 5-4





First make your choice and then read on.

Spoiler

Hitting is tempting for red and it does win more gammons, yet it's a semi-blunder. Right now white has an advanced anchor in red's 4-pt, which is not suitable for a holding game in it's last stages, because the race leader can get his checkers jump over the anchor. Thus, now that red has succeeded in escaping white's onslaught he should favor less contact, considering his somehow inflexible situation. If white lands on red's deep points which is the most probable scenario, red will have difficulties in bear-in and might well leave a shot which will be fatal. Thus, he should follow this advice from Kit Woolsey: when ahead in the race, race!

    1. Cubeful 2-ply    14/5                         Eq.:  +0.745
        88.4%   2.4%   0.0% -  11.6%   0.5%   0.0%
       
    2. Cubeful 2-ply    14/9*/5                      Eq.:  +0.694 ( -0.051)
        81.8%  11.7%   0.1% -  18.2%   1.4%   0.0%
       
    3. Cubeful 2-ply    7/2 6/2                      Eq.:  +0.104 ( -0.640)
        62.4%   5.9%   0.1% -  37.6%   4.3%   0.1%
       
    4. Cubeful 2-ply    7/3 6/1                      Eq.:  +0.021 ( -0.724)
        59.6%   5.9%   0.1% -  40.4%   5.4%   0.1%
       
    5. Cubeful 2-ply    7/3 7/2                      Eq.:  -0.002 ( -0.746)
        59.1%   5.8%   0.1% -  40.9%   5.9%   0.1%
       
Note that hitting wins more gammons, but less games.

[close]

[playBunny]

And the rollout ...

Spoiler

    1. Rollout          14/5                         Eq.:  +0.756
        88.6%   2.2%   0.0% -  11.4%   0.2%   0.0% CL  +0.799 CF  +0.756

    2. Rollout          14/9*/5                      Eq.:  +0.723  (-0.033)
        82.7%  12.2%   0.2% -  17.3%   1.6%   0.0% CL  +0.793 CF  +0.723

      [  0.1%   0.2%   0.0% -   0.1%   0.1%   0.0% CL   0.003 CF   0.004]
      Full cubeful rollout, 1296 games, supremo 2-ply for 12 plies and 0-ply thereafter

Not as drastic an error but hitting is still more trouble than it's worth.

[close]

[PersianLord]

And the rollout ...

Spoiler

    1. Rollout          14/5                         Eq.:  +0.756
        88.6%   2.2%   0.0% -  11.4%   0.2%   0.0% CL  +0.799 CF  +0.756

    2. Rollout          14/9*/5                      Eq.:  +0.723  (-0.033)
        82.7%  12.2%   0.2% -  17.3%   1.6%   0.0% CL  +0.793 CF  +0.723

      [  0.1%   0.2%   0.0% -   0.1%   0.1%   0.0% CL   0.003 CF   0.004]
      Full cubeful rollout, 1296 games, supremo 2-ply for 12 plies and 0-ply thereafter

Not as drastic an error but hitting is still more trouble than it's worth.

[close]

Thanks for the rollouts. 

[mradica]

And the rollout ...

Spoiler

    1. Rollout          14/5                         Eq.:  +0.756
        88.6%   2.2%   0.0% -  11.4%   0.2%   0.0% CL  +0.799 CF  +0.756

    2. Rollout          14/9*/5                      Eq.:  +0.723  (-0.033)
        82.7%  12.2%   0.2% -  17.3%   1.6%   0.0% CL  +0.793 CF  +0.723

      [  0.1%   0.2%   0.0% -   0.1%   0.1%   0.0% CL   0.003 CF   0.004]
      Full cubeful rollout, 1296 games, supremo 2-ply for 12 plies and 0-ply thereafter

Not as drastic an error but hitting is still more trouble than it's worth.

[close]

Which settings you use for cube in this stepped rollout? 2-ply all time or you switch to 0-ply after 12plies as for checker? Anyway, I think 2ply for the cube should be through all rollout.

And for the move, off course red don't like white checker back to make his life difficult. Maybe hit would be right if white's board be less stronger.

[dorbel]

The real question is, "Why hasn't Red doubled?" This is a clear pass now and if Red hits, will always be a pass next turn. Even if not hitting looks minutely better when the game is played to a finish, hitting is correct. Why? Because if Red eschews the hit, White can take next turn after a 6-6. This is called Joker Control!

[mradica]

The real question is, "Why hasn't Red doubled?" This is a clear pass now and if Red hits, will always be a pass next turn. Even if not hitting looks minutely better when the game is played to a finish, hitting is correct. Why? Because if Red eschews the hit, White can take next turn after a 6-6. This is called Joker Control!

I am sorry but Red already sent the cube which is now in white's possession.

[dorbel]

Quite right! I need new glasses! However I would still hit. Why? Because if you don't, White's play is trivially easy; build a board, wait for a shot or run if the race gets close. Hitting him makes for a much more complex game.

[mradica]

Quite right! I need new glasses! However I would still hit. Why? Because if you don't, White's play is trivially easy; build a board, wait for a shot or run if the race gets close. Hitting him makes for a much more complex game.

Hit will give you more interesting game for sure but ahead in race and with gammons not likely much when White has advanced anchor Red job is to break contact not to increase it, especially with white's decent board and prime.   

[PersianLord]

Quite right! I need new glasses! However I would still hit. Why? Because if you don't, White's play is trivially easy; build a board, wait for a shot or run if the race gets close. Hitting him makes for a much more complex game.

I can't match your BG skills even in my dreams, but I think that hitting makes the game much more complex for both sides, not just for white. As said in my blog, red has a relatively inflexible position, with 6 men stacked on the 6-pt and he might well leave a shot later. Thus by not hitting, he can simply get his men jump over white's anchor into safety without the fear of leaving a shot.

And will white really gain an edge in race after a 6-6?

Regards

[playBunny]

Which settings you use for cube in this stepped rollout? 2-ply all time or you switch to 0-ply after 12plies as for checker? Anyway, I think 2ply for the cube should be through all rollout.

I'd never considered that. The cube play is set to match the checker play so I imagine it would revert to 0-ply as well after the 12th play. I'll change those settings to maintain the cube at 2-ply. Thanks for that.

[dorbel]

Hitting maintains contact of course, but Red's play isn't very difficult from here if he hits is it?  Besides, you have to look for more contact and more gammons if you want a chance to outplay your opponent.
6-6 doesn't turn it round for White, but you surely would rather he rolls it from the bar! A play that makes 3 of his best rolls (6-6, 5-5, 6-5) into his three worst rolls is usually pretty good.
For what it's worth, Snowie 3-ply chooses to hit, although I agree that a rollout marginally prefers not hitting. A very considerable factor in this decision is, how well will White use the 4 cube? A lot of players wait too long with a recube, particularly at this score, where Red has to pass 4 cubes that would be trivial money takes.

[PersianLord]

Hitting maintains contact of course, but Red's play isn't very difficult from here if he hits is it?  Besides, you have to look for more contact and more gammons if you want a chance to outplay your opponent.
6-6 doesn't turn it round for White, but you surely would rather he rolls it from the bar! A play that makes 3 of his best rolls (6-6, 5-5, 6-5) into his three worst rolls is usually pretty good.
For what it's worth, Snowie 3-ply chooses to hit, although I agree that a rollout marginally prefers not hitting. A very considerable factor in this decision is, how well will White use the 4 cube? A lot of players wait too long with a recube, particularly at this score, where Red has to pass 4 cubes that would be trivial money takes.

Thanks for the analysis. I will add it to my blog.

By the way, if red doesn't hit and white rolls a 6-6 immdiately after that, should he run with 1 or 2 of his back men or should he keep staying?

Regards

[dorbel]

It's absolutely clear to run with both.
Staying achieves nothing really. White won't get a shot for ages with all those spares that Red has, so he must go and take a chance in the race, even though he trails by 10 pips after the roll. As almost all his wins will come when he rolls well and catches up, it is essential to free all his checkers for the race. You don't want good rolls like 4-4 and 3-3 to be blocked and you certainly don't want to be forced to run with one later, leaving a target behind.