The crucial point of interest in this game is at 10. ... b4- :
[PTN: 1. a5 a1 2. c3 b5 3. d4 c5 4. d5 e5 5. c4 b4
6. c2 c1 7. b2 c1+ 8. b3 b4- 9. b2+ Cb4 10. b2 b4- ]
Here as white, I think I still had some fairly decent control - with fair center influence and connections across the board. The biggest weakness in this position, however, is the black capstone on b3. This capstone, along with the black soldier under it, can do a fair bit of damage and reclaim the middle board. As it is - this is a sort of situation I personally still struggle with a lot.
My goals at this point in the game were simple: Try to extend my influence, block of potential black threats, and create forcing positions. While this sounds reasonable it's a far cry from actually achieving Tinue or a win.
In this trial, I decided to try 11. d3:
[PTN: 1. a5 a1 2. c3 b5 3. d4 c5 4. d5 e5 5. c4 b4 6. c2 c1
7. b2 c1+ 8. b3 b4- 9. b2+ Cb4 10. b2 b4- 11. d3]
At first glance this seems to help the position, by adding support and connections close to the center, and extending the d-file. After black's response, however, it will be obvious why this move is actually detrimental and actually weakens white's position slightly.
To see this, let's follow up with black: 11. ... 4b3>22:
[PTN: 1. a5 a1 2. c3 b5 3. d4 c5 4. d5 e5 5. c4 b4 6. c2 c1
7. b2 c1+ 8. b3 b4- 9. b2+ Cb4 10. b2 b4- 11. d3 4b3>22]
As noted earlier, black was able to take the capstone and the soldier from b3 and gain substantial center control. Not only that, but black now has a powerful Tak threat: 3d3+12 (bringing the capstone up to d5). This threat wouldn't have been possible, however, without the earlier 11. d3 placement! Ultimately, then, black was able to leverage a placed white stone to add range to his active stones - in this case his capstone.
In the end, the real weakness of the 11. d3 move comes from the fact that black was already poised to move across the board with his capstone stack and this piece was put in a location that it could just get sucked up. Ultimately, then, the piece contributed to the height - and effective range of the capstone, allowing black to gain control of the board - and ultimately the game.
This situation reflects two major ideas from a strategic standpoint. From the offensive side, it reinforces the power of stack height. Even though the stacks are weak - with only captured pieces, they allow for a long range influence, enabling them to create Tak threats at a distance. From the defensive side, it demonstrates the importance of anticipating the opponent's intentions and ability to capitalize on moves and pieces - even those just placed.
As it stands, this an incident that I noticed in one of my own games. I would love to hear from any of you about similar situations or positions in your games or experience.
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Think with mind of air
Listen close to heart of stone
A beautiful game