When not to anchor

I am guessing that players around my level are making the same kind of errors that I am. Learning from errors is an important part of improving your game, so I have decided to start a section on the blog to look at some of my errors and hopefully learn from them. In most cases I am adding comments in GNUBG so the discussion will generally be posted in the annotation section of the GNUBG output. While many of these positions are not strictly from Bootcamp I think they are well within keeping with the intent of this blog.

Bots are great, but one of the problems I have with using a bot is to look at a bad play, look at the bot play and say to myself “oh yes that was the right play” without really working through fully understanding why the bot play was better (assuming of course that it was). It took be a while in the following position to figure out why my play was so bad.

Game number 1

The score (after 0 games) is: brspunky 0, BigWill 0 (match to 9 points)

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Match Information

Date	September 28, 2009

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Move number 10: BigWill to play 63

Pip counts: brspunky 134, BigWill 150
Position ID: 4OfBCwBw58IBIg Match ID: UQkvAQAAAAAA

• BigWill moves 24/21 13/7

Cube decision
2-ply cubeless equity		+0.102	(Money: +0.096)
	0.516 0.146 0.003 – 0.484 0.084 0.002
Cubeful equities:
	2-ply cubeful prune [world class]
1.	No double	+0.279
2.	Double, pass	+1.000	+0.721
3.	Double, take	-0.176	-0.455
Proper cube action:		No redouble, take (38.7%)

 

Alert: very bad move ( -0.188)

#		Ply	Move	Equity
	1	R	9/3 6/3	+0.122
			0.459 0.123 0.003 – 0.541 0.082 0.003 -0.040 +0.122 0.003 0.004 0.000 – 0.003 0.003 0.000 0.009 0.010
	2	R	8/2 5/2	+0.120 ( -0.002)
			0.456 0.130 0.002 – 0.544 0.089 0.003 -0.049 +0.120 0.003 0.004 0.000 – 0.003 0.003 0.000 0.009 0.011
	3	R	13/4	+0.096 ( -0.026)
			0.453 0.123 0.003 – 0.547 0.091 0.004 -0.064 +0.096 0.003 0.004 0.000 – 0.003 0.002 0.000 0.009 0.011
	4	R	13/7 9/6	+0.081 ( -0.041)
			0.447 0.115 0.003 – 0.553 0.088 0.004 -0.080 +0.081 0.003 0.004 0.000 – 0.003 0.003 0.000 0.010 0.012
	5	R	13/7 6/3	+0.078 ( -0.044)
			0.448 0.122 0.003 – 0.552 0.096 0.005 -0.080 +0.078 0.004 0.003 0.000 – 0.004 0.002 0.000 0.010 0.011
•	9	R	24/21 13/7	-0.066 ( -0.188)
			0.396 0.029 0.001 – 0.604 0.025 0.001 -0.203 -0.066 0.002 0.001 0.000 – 0.002 0.001 0.000 0.005 0.006

Annotation

I was really surprised about how bad making the anchor on the 21 was
in this position and it took me a while to come up with what I think is the
answer. My best chance at this point is to get a hit on blue. Anchoring on the 21
gives blue the opportunity to play safely behind my anchor where as the current
arrangement of checkers is putting a great deal of pressure on blue. With
blue only having a one point board the risk of getting hit and even pointed on
is not that high, so I am much better off keeping the pressure on with the two
blots for the next roll at least. If I do hit then having another home board point
will be valuable to help contain blue.

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