Note: The analysis and positions described are for the 5x5 game. Extend the principles and ideas to the 6x6 and the 8x8 at your own risk...
In the last few posts, I discussed some theory in regards to the Adjacent Corner Opening in response to the AB line. In this post, I want to take a look at an actual game that was played on this line. My hope is that by looking at player moves, it'll be easier to see some of the impact of the choices of certain moves and how they pan out to the later game.
The game I want to discuss in this post is between two humans, a novice (white) and an experienced player (black). I would recommend following through the game as I discuss the moves in the viewer below or at the following link: Novice-Experienced Game.
I chose to look at this game precisely because it starts with the opening line that I discussed in my previous posts: 1. a5 a1, 2. b1.
To start, black follows up with 2. ... d2, a move I analyzed a decent bit in the few posts. White decides to continue pressure across the 1-row with 3. c1. Black here decides to respond with 3. ... d1, cutting white off - responding much the same as I had suggested in my post. Rather than cede control or divert attention, though, white decides to continue to pressure the 1-row with 4. e1?. This move is understandable, but ignores tempo and the board. Unlike the previous moves, it's not as forcing. Black has already cut the 1-row, so there is no immediate threat that this creates. Furthermore, it ignores plays that would increase influence or even contest black's growing influence on the d-file or the center of the board in general. A more typical play would have been 4. c3 or 4. c2.
Black capitalizes on this play by responding 4. ... c2! In my opinion, it is a move like this that really shows that Black is a fairly experienced player. As noted, white had the ability to extend into the center. This move cleanly reduces the amount of influence white can create, while building black's influence and even starting to build a potential lines on the 2-row. As a result, this move is quite strong.
White here continues to pressure the 1-row with the move 5. 1e1< . In general, captures tend to be a lower tempo and influence gain than placing a piece - a theory that I may expound on more in the future. As a result, captures - especially in the early game - should be considered carefully and should provide equivalent advantage. In this case, however, the only advantage is a road threat that is easily countered.
Black responds by playing 5. ... e1. I would suspect that white had actually anticipated d2-, with a follow-up capture, which would have been marginally in white's advantage. However, black intelligently realizes that the road threat can be counter with a placement that threatens the d1 square - white's main source of power. Of the options to defend against white's line threat here, I would consider this the best.
White follows up with a cut and new road threat: 6. e2. This threatens a future e2-, finishing up the 1-row road. As with most of white's moves in this game, it is too focused on the immediacy of this one road, and misses out on blacks growing advantage and abilities. (Which we will see develop shortly).
Black presses back with 6. ... e1<!. Again, black here demonstrates a powerful and thoughtful move. Granted, there are only a few options to block the road threat, but both d2- and d2> (moving the d2 stone to capture an adjacent piece) would have been substantially weaker. Instead, black captures the offending d1 stack which regains control of a black piece, defends against the road threat, and even builds black influence along the d-line. In contrast to the earlier capture by white, this capture easily matches the potential tempo cost.
At this point, black has a substantial advantage. White has no more immediate line threats, so can't really pull black into fights or create forcing moves. At the same time, black has better advantage. And with black's stack at d2, black has some flexibility for expansion. Even if white were to now shift attention to the center board and breaking up black, it is at a move and piece disadvantage for doing so.
Effectively, by controlling this opening, and pacing appropriately, black has deterred a seemingly aggressive opening and turned it to his own advantage.
At the same time, the game is not yet won at this point. With experience play on both sides, white could potentially have gained some space and influence. One of the weaknesses of black's structure is that the pieces on the 1 and 2 rows are disconnected from the black corner piece. In addition, black doesn't have great influence on the center. A good center (c3) play could substantially help white by adding pressure to black (defending against the 2-row and d-file threats, but a flat stone would be at risk. A standing stone or a capstone, would be able to hold the square and create these threats without immediate reprisal. Alternatively, a center-adjacent play could help gain territory and space, while enabling some maneuverability to defend against black threats. Or, perhaps, a play on the e-file could extend white's influence bringing it up and into the center. (I'm not as enthusiastic about this last option, though).
Regardless of white's move, black has a lot of strong options to maintain and gain control. It is, however, well beyond the scope of this post to analyze every possible response or line. As such, I would encourage readers to try this situation out themselves. Through this sort of experimentation, I believe that any player - experienced or novice - can gain meaningful insight into the effect of the opening and the various influences that different moves or positions can have on the game.
Because of the nature of this situation, this move (6. ...e1<!) is actually a good place to end my analysis of this game. With black's clear advantage and the lack of white's experience, the rest of this game is simply a fairly methodical progression to black's victory.
Overall, I hope that this analysis shows some of the mechanisms in this line, along with some of the differentiations between novice and experienced play.
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Think with mind of air
Listen close to heart of stone
A beautiful game
Teaching the art of Tak