[ View Thread ] [ Post Response ] [ Return to Index ] [ Read Prev Msg ] [ Read Next Msg ]

BGonline.org Forums

Point-shifting finesse

Posted By: Nack Ballard
Date: Wednesday, 16 September 2015, at 10:39 p.m.

In Response To: PUZZLE (updated position) SOLUTION (Nack Ballard)





White is Player 2

score: 0
pip: 6
1 point match
pip: 118
score: 0

Blue is Player 1
XGID=--BBBCC-------------aB--aA:0:0:1:11:0:0:0:1:10

Blue to play 11


[This is the second diagram posted here, with the score corrected to DMP.]

Stick ended his solution with Blue rolling 41 in the position above. To this, I commented, "If Blue is assigned a roll of double 1s (instead of 41), he gains a crossover, but it turns out to make no difference..."

In the heat of puzzledom, I temporarily forgot that both sides are playing real backgammon. Instead of gaining a crossover in an attempt to get off in the fewest sets of double 6s, Blue should be trying to win without the ability to dictate future rolls!

Duane Jensen astutely reminded me that the best backgammon play with double aces is the point-shift bar/24* 21/20 2/1(2). If White is fortunate enough to anchor, Blue would rather it be on his 2pt (than his 1pt), so that White will have to run with 5s. In other words, shifting from the 2pt to the 1pt is a conditional trap play.

How far should one extend this point-shifting logic? Consider the five (DMP) positions below. I'm not planning to follow up with rollouts, but if someone else wants to do rollout(s), feel free. (Move around the spares, if you like, too.)

Nack





White is Player 2

score: 0
pip: 5
1 point match
pip: 130
score: 0

Blue is Player 1
XGID=--BBBBB-AA------------aaBA:0:0:1:22:0:0:0:1:10

Blue to play 22
White is Player 2

score: 0
pip: 7
1 point match
pip: 130
score: 0

Blue is Player 1
XGID=--BBBBB-AA-----------aa-BA:0:0:1:33:0:0:0:1:10

Blue to play 33
White is Player 2

score: 0
pip: 9
1 point match
pip: 130
score: 0

Blue is Player 1
XGID=--BBBBB-AA----------aa--BA:0:0:1:44:0:0:0:1:10

Blue to play 44
White is Player 2

score: 0
pip: 11
1 point match
pip: 130
score: 0

Blue is Player 1
XGID=--BBBBB-AA---------aa---BA:0:0:1:55:0:0:0:1:10

Blue to play 55


Messages In This Thread

 

Post Response
Your Name:
Your E-Mail Address:
Subject:
Message:

If necessary, enter your password below:

Password:
 

 

[ View Thread ] [ Post Response ] [ Return to Index ] [ Read Prev Msg ] [ Read Next Msg ]

BGonline.org Forums is maintained by Stick with WebBBS 5.12.