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Game number: Main Page
White: Csaba Nagy    Black: pete99
twixt.ch.22.2.2 (LG) | This game (LG) | Download JTwixt file
On 2009-08-24 at 02:02, pete99* (info) said:
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COMBINED COMMENTARY by Csaba Nagy and pete99

Csaba Nagy: Greetings! This is my first comment here. I try to write down how I chose what to play.

pete99: Hi! I have tried to show what I was considering at several key points, how I came up with some good moves that made the game very difficult for a much better player, and finally some lessons learned about how one assumption I made during game play caused me to choose a wrong move at not just one critical point, but two!
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MOVE 4 by Csaba Nagy:
4.j15 is far down to try hard stop 5.l15.
6.o8 is far again for inner approach 7.m9. 8.l7 directly shades it from the top, but not the other white peg as 9.i8 shows.
With 10.l17 hard stop black again shades only one peg now from the bottom. White 11.q17 is in good relation with 5.l15 - as (5,2) usually is - and aspires upward on the empty right, with 13.q13 later.

MOVE 12 by Csaba Nagy:
Black 12.m15 and 14.o12 tries to separate the right side, without success. I feel after 10.l17 it is too late to look for better solution for black.

MOVE 12 by pete99:
By move 12.m15, Black already knew he had been out-maneuvered in the early positioning. In particular, the top and bottom peg groups now seemed too far apart. After 13.q13 Black tries to squeeze through a connection to the o8 peg using 14.o12. Black had hopes of making this connection work by using an o12-p14 link as a threat to the right. But White's 15.n14 ensured that o12-p14 link threat option was no longer workable and put an end to those hopes.

MOVE 15 by pete99:
White's 15.n14 forced a new approach. Black instead threatens bypassing q13 with 16.m13 and finally is able to connect to the o8 peg when White defends with 17.p10 against Black's direct path to the right side. But the main purpose of 16.m13 had been to threaten the connection to m15 via o14. That threat is the only thing preventing White from using 19.k13 for an easy win.

MOVE 15 by Csaba Nagy:
After 15.n14 16.m13 17.p10 18.n10 the right side is still not separated completely. This fact misled me and played 19.p15, I thought I have two chances to reach the top on the right or on the left. 20.o4 which efficiently protects both side showed me my mistake.

19.q8 would have been the good choice. Black has no chance:
20.r9 21.s9 22.r13 23.s14 24.q11 25.t12, or
20.s8 21.s7 22.r13 23.s12 24.p14 25.r14, or
20.p13 21.p11 22.r14 23.o13 24.o15 25.o16 26.o14 27.k13.

MOVE 19 by Csaba Nagy:
Back to the game, after 19.p15 20.o4 21.q8 doesn't work as we will see.
21.j14 needed for keeping open the left side top connection.

MOVE 19 by pete99:
Black was disappointed but not surprised when White played 19.p15. With White now thoroughly controlling the bottom right, if Black tries either going left or right within the center area, then White wins by using the other path. At this point the top part of the board still does remain largely open and Black has no choice: there is nowhere else but there having any available playing space left to use.

A drop-back-by-4 move by opponents has been difficult for pete99 to deal with in the past, so he tries it here with 20.o4. If White closes the lower left side with 21.k13 or 21.j14, then Black can go horizontally across the top to block White.

MOVE 22 by Csaba Nagy:
22.i5 is a good choice (6,1) connection to both sides. This shape can be attacked only from (2,1)(4,0) points.
In this situation 23.m4 doesn't work:
23.m5 24.n6 25.h6 26.g4 27.j5 28.k4 29.l3 30.l6 or 27.k6 28.j6 29.j5 30.k4
23.k4
almost good.
24.j6 25.h6 26.g4 27.j5 not good for black.

24.k6 25.l6 26.m7 may help white just he has to manage to put a peg on 27.p6 while threatening top right connection.

23.q8 too late. 24.s4 the missed chance for black: 25.o5 26.p6 27.m4 28.n6 29.h6 30.g4 31.j5 32.k4

MOVE 24 by pete99:
Black had considered both 24.s4 and 24.q5 as options at this point. 24.s4 looked like a win, but there was a lot of open space for White to use for playing room across the top of the board, and white had the choice two different directions from which to advance. Without seeing exactly how White might win, Black was nevertheless concerned that a very strong player like White would spot something that Black had missed. For this reason Black also took a look at 24.q5, and ultimately chose that losing move instead of the winning move 24.s4.

Lesson Learned: Black's *incorrect* reasoning was as follows… if 24.q5, then the right and left sides of the top of the board will become two separate small games, and there is a good chance that Black could win each of these "small games" if handled separately. Black realized that getting through from 24.q5 to the right side of the board would be difficult – and it was – but believed that he could eventually work into a spot that would give him the option of connecting either to a black peg near the top of the board or to black the peg at o12, and that this potential dual threat should permit Black to reach the right hand edge of the board. Black did ultimately reach the right side, but only at the cost of leaving gaps among the black pegs that White could exploit for a win. In the end, White *was* able to bridge together the left and right sides, demonstrating the error in Black’s original assumption that the upper right play had been separated from the upper left.

MOVE 25 by Csaba Nagy:
After 24.q5 one way: 25.u6 26.s7 27.t9.
Closing the side28.t5 29.v4 30.u3 31.u2.

32.t10 is not good:
33.u11 34.s8 35.t8 36.u12 37.r6 38.s6 39.r7 or
34.s12 35.t14 36.t15 37.u16 38.s13 39.t13 40.u17 41.r12 42.q12 43.p11

32.u9
the right choice, 33.t8 34.s10 35.p11 building the trap, with 36.r8 black is in it. Now white can win with 37.p6 (the order is different).

If black avoids the trap, then draw:
36.r9 37.r10 38.s8 39.r6 40.s4 41.t6

MOVE 36 by pete99:
Pete saw that 36.r9 offered a draw, but here his earlier incorrect assumption (i.e., about the upper left and upper right being separated areas of play) still biased his thinking, and led him to a make yet another serious mistake. Earlier he chose the the lose-or-draw move |24.q5 instead of the winning move |24.s4, and now for the same reasoning he chooses the losing move |36.r8 instead of the draw with 36.r9.

Lesson Learned: Black's *incorrect* reasoning was that the draw only affected the upper right, and that if White could win on the left, he would anyway, whether or not there was a draw move in effect for the upper right. When taking the upper right by itself as a separate problem, |36.r8 does lead to a “local” win. Pete still might never have spotted the clever bridge structure that Csaba constructed, but the really fundamental error was remaining trapped by an incorrect assumption, and not even trying to seriously look for the possibility of a left-right-spanning bridge in the endgame.
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CLOSING THOUGHTS by pete99
This was an intriguing and enjoyable game. I am almost glad it worked out the way it did, because if I had played |24.s4 in the first place, I would have missed out on what I learned from this intricate endgame. If you look back at the board as of |36.r8, you can see that it does not look like White has much to work with. There is a sizable area (from b2 to t7) having no white pegs at all. My congrats to Csaba on figuring out and setting up an effective and not-so-obvious bridge, within that, spanning a surprising 4 rows and 9 columns!
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