One was that the White move shown is an invasion, not a reducing move. I think it is worth maintaining the traditional distinction because it makes it easier to talk about strategy - see below.

The more important thought was that this can't possibly be a textbook position. It is just a conglomeration of textbook sub-positions. The reason it can't be a textbook position is that it is surely bad for Black. He has a position at the top which invites invasion, but whether he encloses the invader and makes thickness or chases it out to the centre, there is nothing Black can gain because White has solid positions to left and right of Black's upper shape. Therefore Black must have done something wrong earlier on.

To confirm this, I did a Kombilo search. The position has never appeared in pro play. Taking the position in the bottom half only, that has appeared 17 times in actual play (out of 78,000 games; interestingly, five of those examples were by Cho Hun-hyeon).

...this can be done by playing a traditional reducing move such as K15 and K16 (leaving horrible aji for Black at the 3-3 point in the upper right), and then using sente to expand White's moyo prospects on the lower side.

Invasion of the upper side by White will also take away points from Black, of course, but like all invasions it runs a very high risk of ending in gote, which would give Black the chance to negate White's potential on the lower side.

However, there is a third option, which is the one apparently most favoured by pros...

in each case at the mole invasion point of Q18.

More to the point in terms of the OP is that the attachment at the 4-3 point is extremely rare. The position below with a Black stone on the side occurs about 1,000 times in GoGoD. White played only three times. In contrast "a" was played 203 times and "b" 55 times. In fact White did not rush to the corner in any case. And by the way, Black answered on the outside at in all three games. In general the outside play occurs in actual practice much more often than the inside play.

Click Here To Show Diagram Code

[go]$$Wc Continuations
$$- - - - - - - - - - - - - +
$$. . . . . . . . . . . . . |
$$. . . . . . . . a b . . . |
$$. . X . . . . . 2 1 . . . |
$$. . . , . . . . . X . . . |
$$. . . . . . . . . . . . . |
$$. . . . . . . . . . X . . |
$$. . . . . . . . . . . . . |
$$. . . . . . . . . . . . . |
$$. . . . . . . . . . . . . |
$$. . . , . . . . . , . . . |
$$[/go]

Sure, let's call it an invasion.



While off-topic to the question I (now, somewhat regrettably) posted, I disagree with your assessment. Black's play, while uncreative, has solidly gained points, and the top side cannot be said to be black's points, anyway - it's just the next big area to play in the opening.

If black were trying to profit from a moyo on top, you might be correct, but black's choice of joseki in the top left is clearly a territorial choice. Black has already made profit from the solid points he has made.

If black has made a mistake earlier on, what was it?




From a whole board perspective, this is close to meaningless. The number of variations in the game make it unlikely for a given player to even play the same game twice. When people do these database searches of positions, later in the opening, the pattern results are always just a handful (10 or 20, or in some cases, maybe 2 or 3 matching positions).

Pattern searching can be useful for local positions, but it starts to lose power in whole board positions. As a test, take the next pro tournament from any country, and pick an upcoming game. I can bet that the game diverges from game databases before the middle game starts. It doesn't mean that the game is bad - it just means that the combinations of moves are great, and it's unlikely to get exactly the same game twice.

This being said, I feel both black and white's play lack creativity - they are playing basic josekis, but I don't see where any player has played poorly to fall behind.

This position came from a go lecture, and I feel it is a reasonable opening for both sides.

If you find a pro player who says this position is bad for black, then I will consider the argument, but I will still be wondering why they feel that way. A database search, on the other hand, is not convincing to me from this whole board position, this late in the game.



Interesting idea to try to get sente. In my opinion, the invasion will probably get more points for white locally, but depending on the board position, it might be good to give this up to achieve sente.



If you are going to be trusting the database search, and you don't feel this is a "textbook position", then how is it possible for you to make conclusions here on the option "most favoured by pros"? If this position doesn't appear in your pattern search, then how do you know where most pros will play here? Perhaps you are comparing to similar positions, but is this analysis possible with a "non-textbook" position? Maybe the top half of the board is the same, but this says nothing conclusive about the quality of the position here.


I agree that Q18 is a good option, and I use it sometimes in games.

To be clear, I don't care about the board position here as much as I wanted to set up a feasible example of the sequence in question. Maybe I shouldn't have used the word "textbook" - my point was just to set up a position for illustration.

I appreciate that you've given some alternative options to making the invasion in the first place, but I feel more like the intention of your post was to attack the choice of wording that I used.

While I have some disagreements even in this critique, as described above, it doesn't matter to me strongly if this position is a "textbook" position. I saw it on a lecture, and the lecture was discussing various invasions in the top right area. I agree that the invasion in question may not always be best, but all I am curious about is the invasion, itself, which others have kindly commented on.

If it makes more sense, let's refer to this board position as a "mickey mouse" position, rather than a textbook position - it makes little difference to me. I simply wanted to ask about alternative followups to a choice of invasion from this mickey mouse board position.

Thanks, Dave. Yes, I agree that the alternatives posed in your last diagram may be better here. Still, I was mainly curious about the 4-3 option in general, and I just needed a board position to set it up on.

Perhaps the one I selected wasn't the best example.

Click Here To Show Diagram Code

[go]$$Wcm1 Black: 0 White: 0
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . X . . |
$$ | . . O . . X . . # . . X . . O O X . . |
$$ | . . . O . . . . . , . . c . O X 2 . . |
$$ | . . . . . . . . . . . . . . . 1 . a . |
$$ | . . O . . . . . . . . . . b . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 3 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . O . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . X O . . . . . , . . . . . X . O . |
$$ | . . X O O X . O . . O . . X . . X . . |
$$ | . . X X O . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Territory-oriented players will find the / exchange unbearable. Not only the territory in the corner is reduced, but also some aji can be exploited later. For example, is a large move, leaving further reduction at 'a'. So in my opinion black actually loses many points here.

The 4-3 attachment is much more applied to the position after the large knight's extension from the 4-4 stone, and the inside hane is also more frequent in that case. Besides the same issue comes up, in a slightly different form.

Click Here To Show Diagram Code

[go]$$Wc Joseki with same question
$$- - - - - - - - - - - - - +
$$. . . . . . . . . . . . . |
$$. . . . . . . . . . 4 . . |
$$. . X . . 7 . . 3 1 2 . . |
$$. . . , . . . . . X . . . |
$$. . . . . . . 5 . 6 . . . |
$$. . . . . . . . . . . . . |
$$. . . . . . . . . . X . . |
$$. . . . . . . . . . . . . |
$$. . . . . . . . . . . . . |
$$. . . , . . . . . , . . . |
$$[/go]

Why not at 7?