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Old 02-25-2017, 10:06 PM   #1
midiboy
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Boston Open - Robertie v Klein - Position Best Play?

What's your play in this situation?

Bill Robertie vs. John Klein, 2017 Boston Open
Klein leads 4-3 in a 9-pt match
White (Robertie) Pips: 184

Black (Klein) Pips: 151
White to Play 6-4
Created with www.BGdiagram.com
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Old 02-26-2017, 05:02 AM   #2
Don Kament
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Re: Boston Open - Robertie v Klein - Position Best Play?

Hi,

this is a type of position where i constantly make the wrong decision. Iīm always somekind of lost when something like this happens.

I think i would play Bar/15 for reasons i could not explain - and thatīs why i bet itīs wrong... If so iīm looking forward for an explanation of an expert.

Last edited by Don Kament; 02-26-2017 at 05:13 AM.
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Old 02-26-2017, 04:18 PM   #3
Karol Szczerek
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Re: Boston Open - Robertie v Klein - Position Best Play?

I might blunder here, too, but I'd seriously consider coming down with 13/7. I've seen such plays so often being correct in midgame, that I wouldn't be surprised if it was the case also here.

What are the alternatives?

24/18 leaves 4 blots, opp will have many double shots, which will be killers if we can't hit back immediately. Also, no point means that we can be swooped. He has many builders in the zone, and holds an anchor for safety. Dangerous.

21/15 is too passive. It's like slowly handing him the victory. Look at the position - we have a stranded ace point behind broken 3-prime, which will soon turn into a stronger prime. He's got an advanced anchor. I think he might actually be in the doubling zone after this play.

8/2 is even worse.

13/7 is like a last chance to contest him. The 2s are duplicated. If he double-hits, he has to break the anchor to do it, so there's some slight retalation prospect for us. If he make a blocking point other than the 4pt, we can cover for an anchor. If we get swooped, we might form some sort of backgame.

All moves look bad, but to me, 13/7 looks best among them.
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Old 02-26-2017, 10:16 PM   #4
midiboy
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Re: Boston Open - Robertie v Klein - Position Best Play?

This is a position I would normally play bar/15 - the 3rd best option in this case. Bill correctly played 13/7. I was surprised to see bar/21 24/18 as a reasonable alternative, but GNU rollouts demonstrate that 13/7 is clearly best.



Karol's explanation certainly seems solid. Perhaps Bill can chime in at some point to share his thoughts, but this position play will cause me to give serious consideration to choosing an alternative move in lieu of running my bar checker almost out of habit.

Here's video of the match that picks up at this roll; clearly Bill gave this move some serious thought:

https://youtu.be/pl_ZuFE21TA?t=1563

Bill went on to win this game from behind, and won the match. This is a good match to study with many challenging positions.

Last edited by midiboy; 02-26-2017 at 10:41 PM.
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Old 02-27-2017, 03:33 AM   #5
Don Kament
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Re: Boston Open - Robertie v Klein - Position Best Play?

Quote:
Originally Posted by midiboy View Post
This is a position I would normally play bar/15 - the 3rd best option in this case. Bill correctly played 13/7. I was surprised to see bar/21 24/18 as a reasonable alternative, but GNU rollouts demonstrate that 13/7 is clearly best.



Karol's explanation certainly seems solid. Perhaps Bill can chime in at some point to share his thoughts, but this position play will cause me to give serious consideration to choosing an alternative move in lieu of running my bar checker almost out of habit.

Here's video of the match that picks up at this roll; clearly Bill gave this move some serious thought:

https://youtu.be/pl_ZuFE21TA?t=1563

Bill went on to win this game from behind, and won the match. This is a good match to study with many challenging positions.
Thx for the link!
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Old 02-27-2017, 11:13 AM   #6
Robertie
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Re: Boston Open - Robertie v Klein - Position Best Play?

Yes, I remember this play. It was from Friday's qualifier to get into the Master's.

This was basically a process of elimination. I call this position a 'random 6 from the bar' play'. In the opening, the default is 24/18, since you're not risking much in the race with that play. But if you have a blot on the 20 or 21-point, 24/18 isn't so good because your opponent will have plenty of double-hits.

On the other hand, Bar/21/15 doesn't look so good because your back checkers are still on the 24-point. With your opponent having an advanced anchor you need one too, but now you're going to have to spend some time picking up your outfield blots, so an advanced anchor won't be so easy for White to get.

So now you look at 13/7 and by comparison, that doesn't look so bad. Your opponent has no board, so you don't need to be too worried about outfield blots, and you've got the 21-point slotted, which helps you get an anchor. I may get a bunch of men hit, but with Black having no board, I'm not that worried yet.

One further note -- I was surprised that GNU rated 24/18 so close to 13/7, so I just rolled this position out in XG and it rated 24/18 as a blunder (-0.081) which seems more correct to me.
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Old 02-27-2017, 09:18 PM   #7
midiboy
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Re: Boston Open - Robertie v Klein - Position Best Play?

Appreciate the explanation.

I was also surprised how 24/18 rolled out - I rolled the moves out again in GNU with a tougher set of options and got some different results:

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Old 02-28-2017, 03:54 AM   #8
midiboy
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Re: Boston Open - Robertie v Klein - Position Best Play?

I rolled out the top 3 moves in XG: (I don't know how to use XG very well so I hope I did it correctly)

1. Rollout Bar/21 13/7 eq:-0.636
Player: 36.14% (G:6.82% B:0.48%)
Opponent: 63.86% (G:23.05% B:2.64%)

2. Rollout Bar/15 eq:-0.649 (-0.013)
Player: 35.78% (G:6.61% B:0.48%)
Opponent: 64.22% (G:23.87% B:1.91%)

3. Rollout Bar/21 24/18 eq:-0.691 (-0.055)
Player: 35.69% (G:6.52% B:0.45%)
Opponent: 64.31% (G:26.59% B:2.28%)
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Old 03-01-2017, 09:49 AM   #9
cboevey
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Re: Boston Open - Robertie v Klein - Position Best Play?

Part of my thinking in these positions, when I take the time to think and not just play the first blunder that pops into my head, is where can I leave a blot where my opponent must concede the most in the event of a hit. If he hits in the outfield, he strips his midpoint which is something. However, if he hits on the 11 or 7 point he gives up his anchor which will be worse for him.
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Old 03-01-2017, 08:27 PM   #10
midiboy
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Re: Boston Open - Robertie v Klein - Position Best Play?

Yep - having him break up that anchor on the all-important 5-point is an important consideration for this play. (As opposed to playing the first blunder that comes to mind.)
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