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Topic: Win as P1 in this common DB position with best defense & be a pente legend.
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watsu

Posts: 1,097
Registered: Dec 16, 2001
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Win as P1 in this common DB position with best defense & be a pente legend.
Posted: Nov 7, 2017, 4:11 AM

Here's a challenge for all you aspiring Pente legends:
This position is relatively common in the database and apparently this was a popular 7th move for P1 back around the turn of the century. The challenge here is twofold:
First, find the best defense against the position.
Second, win as P1 in spite of P2's best defense. Accomplish both, and become a Pente legend.




I don't want to play non tournament rules games. If you take one of my unrated invites, play tourney


gd_barnes

Posts: 8
Registered: Nov 28, 2015
From: Kansas
Age: 56
Re: Win as P1 in this common DB position with best defense & be a pente legend.
Posted: Nov 9, 2017, 9:23 AM

Watsu, I may have made an error in the analysis that we discussed at IYT. I'm still looking at this position.



watsu

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Re: Win as P1 in this common DB position with best defense & be a pente legend.
Posted: Nov 9, 2017, 5:47 PM

Sorry Gary, but you're already a Pente legend - no extra credit

I don't want to play non tournament rules games. If you take one of my unrated invites, play tourney
gd_barnes

Posts: 8
Registered: Nov 28, 2015
From: Kansas
Age: 56
Re: Win as P1 in this common DB position with best defense & be a pente legend.
Posted: Nov 9, 2017, 9:59 PM

Ha ha.

It turns out the analysis at IYT was correct. Late last night, I had found a line where I thought P1 could win against P2's best defense. But that is not the case. I now stand by the statements that I made to you at IYT.

Maybe give it a couple of weeks and then you or me can post the best defense for P2 and then see if anyone can come up with a winning line for P1. If that is possible it will be very complex.

For everyone else, as a backdrop to this: This is a position that I played as player 1 back in an IYT tournament in 2000. White's 7th move was fairly common then but it is an error. Watsu and I discussed it for a while recently at IYT. He brought it up and said he thought that player 1 had a "sure loss" in the position. After extensive analysis I agreed.

This goes to show that new lines can still come out of old commonly played positions.

Alas, player 1 can still win fairly easy with at least two other 7th moves that ironically are not nearly as common in the DB.

richardiii

Posts: 366
Registered: Dec 8, 2002
From: Huntsville, Alabama
Age: 63
Re: Win as P1 in this common DB position with best defense & be a pente legend.
Posted: Nov 14, 2017, 2:46 AM

Jeez, Gary Barnes is still around. In the shadows a little but hey, it's good to see you are paying attention some.

I can see about 3 other options to white's G7 that look interesting, though G7 itself is a wonderfully complex sequence.

I'd love to explore them with you one day Dr. Barnes. You Da Man!


Message was edited by: richardiii at Nov 14, 2017 4:11 AM


watsu

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Re: Win as P1 in this common DB position with best defense & be a pente legend.
Posted: Nov 20, 2017, 3:38 PM

The key moves for P2 in this position appear to be 7. ... G10 (played first in order to prevent potential extensions by P1 on the 10 row) followed by 8. ... H7. If P1's replies are anything besides 8. H9 and 9. K9, those other options appear to only make the position worse for P1. After 9. K9, I initially explored P2's next possible move as 9. ... K11, which appears to me to be a winning move, though P1 has many choices after this move which can alter P2's (probable) winning continuation. Gary came up with 9. ... H11, which also appears to win for P2, but possibly more quickly and easily than 9. ... K11, depending on P1's replies. In order to solve the line of 7. G7 as a win for P1, both of these ninth moves by P2 will need to be analysed and addressed. Don't worry, despite my original requirements, finding a winning P1 line against 7. ... G10 and P2's lines after that move still qualify one for Pente legend status.





Message was edited by: watsu at Nov 20, 2017 4:14 PM


I don't want to play non tournament rules games. If you take one of my unrated invites, play tourney
gd_barnes

Posts: 8
Registered: Nov 28, 2015
From: Kansas
Age: 56
Re: Win as P1 in this common DB position with best defense & be a pente legend.
Posted: Nov 21, 2017, 8:09 AM

As Watsu stated here, 9...H11 is likely P2's best attack option. Against 9...K11, P1 has 10. K8, which leads to murkier waters, although I believe P2 still wins.

P1's 7th move is most likely losing. I believe his best moves are likely 7. H7 or K8. Watsu had reported that top players more recently had been playing 7. H7 against him.

I'd be amazed if anyone could come up with a winning line for P1 against 7. G7 G10 8. H9 H7 9. K9 H11.

brf

Posts: 172
Registered: Jan 23, 2002
From: Forest Grove, Oregon
Age: 47
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Re: Win as P1 in this common DB position with best defense & be a pente legend.
Posted: Nov 23, 2017, 7:10 AM

I looked at it too, and after 9. K9 H11 I couldn't find anything that lets P1 get any kind of initiative. P2 can easily start taking apart P1, forcing a win by captures in a multitude of ways....depending on what P1 tries.

Until recently when Watsu and I were looking at this line one evening, I don't think I've ever as P1 had the stones play out to 6. H10 J8 for me to attempt 7. G7 G10 either. So this is a new wedge trip for me and I spent some time trying to find a flaw in it, and really couldn't.

Based on what I can tell, P1 is screwed from the 7. G7 G10 placement. P1 needs the rewind button and a different strategy in order to get out of that mess.

So, I'm with Gary, if there is a winning line for the stone placement of moves 7. G7 G10 8. H9 H7 9. K9 H11. (or even just 7. G7 G10) I couldn't find it...nothing but pain and suffering down that road for P1 as far as I can tell.

dmitriking

Posts: 375
Registered: Dec 16, 2001
Age: 40
Re: Win as P1 in this common DB position with best defense & be a pente legend.
Posted: Nov 23, 2017, 1:47 PM

You guys are such noobs. It took me about 30 minutes to figure out how to defeat both H11 and K11 as black's 9th move.



watsu

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Registered: Dec 16, 2001
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Re: Win as P1 in this common DB position with best defense & be a pente legend.
Posted: Nov 23, 2017, 4:24 PM

Uh oh guys, I think Dmitri just discovered the 10. C6 gambit, wherein P1's 10th move can change the game to connect 6 and grant P1 2 moves on the same turn...



I don't want to play non tournament rules games. If you take one of my unrated invites, play tourney
brf

Posts: 172
Registered: Jan 23, 2002
From: Forest Grove, Oregon
Age: 47
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Re: Win as P1 in this common DB position with best defense & be a pente legend.
Posted: Nov 23, 2017, 5:55 PM

better keep it on the downlow dmitri, you just might be able to pull that magical line off in the next tournament. I'm assuming that the move you have identified is depressing the blue "resign" button below the board? Undoubtedly that would be a winning move of sorts.

gd_barnes

Posts: 8
Registered: Nov 28, 2015
From: Kansas
Age: 56
Re: Win as P1 in this common DB position with best defense & be a pente legend.
Posted: Nov 23, 2017, 7:38 PM

Not a chance. I don't believe you!

If you did find a winning line for P1, there is no reason to keep the line secret. Top players would never play P1's 7th move now when other moves win easily.

Go ahead, post the winning lines for P1, especially the one that defeats 9...H11. I dare you!

dmitriking

Posts: 375
Registered: Dec 16, 2001
Age: 40
Re: Win as P1 in this common DB position with best defense & be a pente legend.
Posted: Nov 23, 2017, 11:29 PM



As you all have figured out already, I was joking.

It definitely seems pretty hopeless. The fact that no one took me seriously indicates how bad the position is for white.

Of course, my first sentence was intended to make it clear that I was just goofing around, but now the set-up is in place for the next time I really so solve one of these unsolvable puzzles.



gd_barnes

Posts: 8
Registered: Nov 28, 2015
From: Kansas
Age: 56
Re: Win as P1 in this common DB position with best defense & be a pente legend.
Posted: Nov 29, 2017, 5:26 AM

As previously alluded to, in the original position, P1 wins fairly easily with a better 7th move. 7. H7 apparently wins by force in 11 additional moves on move 18. I'm also a fan of 7. K8 but I think it takes a bit longer to win with best play. This appears to be the best play by both sides:

7. H7 K7 8. H9 H11 9. H8 G7* (K6* and H6 lose more quickly)

10. H7 H6 11. F10 G10 12. E12* G10 13. F8 G8 14. J5* K11* 15. H9 H6 16. F9 F11 17. J12* and wins next move.
-or-
13...J5 14. G8 K4 15. L3 K11 16. F7 E6 17. F9 and wins next move.

I had a little assistance from Mark's AI on this.

watsu

Posts: 1,097
Registered: Dec 16, 2001
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Re: Win as P1 in this common DB position with best defense & be a pente legend.
Posted: Nov 29, 2017, 5:08 PM

Interestingly, the 7. H7 K7 line isn't in the database. I suspect this may be because even though by the definition of prolonging the game as long as possible against best play 7. ... K7 makes sense, it actually doesn't appear to offer as much in the way of opportunities for P1 to fail to find best play as some other 7ths. I prefer 7. ...K11, which likely loses by force on move 17 with best play, I suspect, though perhaps there may be a quicker win for P1. If so, I haven't seen it yet. Other players have had TB success with 7. ... G7, but I have not and I personally think it leads P1 towards 8. G8, which appears to win pretty quickly.


Message was edited by: watsu at Nov 29, 2017 5:09 PM


I don't want to play non tournament rules games. If you take one of my unrated invites, play tourney
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