W+18.5 How does black get it back?

RazorBrain · #1

Played a game last night and felt pretty good about it, except for the 18.5 white lead at the end LOL. As I went back through it, I didn't spot one obvious blunder (doesn't mean there isn't one, eh?). Your opinions and comments are appreciated!

amnal · #2

9: Generally bad. You make white's shape strong without defending the corner (unless you add more moves, inefficiently). This isn't as good as it looks, as C17 still works for white.

11: Generally very bad, you are trying to play in too many places at once. Now white can play E16 and seal black into the corner. This is an overplay.

12: An underplay, white does not see the E16 tesuji.

17: My instinct is to double hane here. White's cut is annoying, but it lets you make thickness in sente and you get C3 later.

31: 'Too late' for what? It is very boring for white to play here, he is already strong. In fact, there is some weakness to aim at in his corner shape (R3 nearly still works). The only reason to play O5 is if you think it helps with your moyo building...maybe it does, but 'before it was too late' seems like bad reasoning. I think perhaps you can play something like B14 instead, aiming to actually attack something if white takes sente.

33: Nooo! A terrible attitude. If white can seal you in in sente, find a way to make it gote for him. If you really can't stop him, think really hard about whether you want to let him. If (most of the time) you really don't want to let him, push out sooner. Being sealed in may not be bad here, but taking gote with a small move is the wrong way to respond - at the very least, play something like B14 to fix your aji.

(The rest of the game also has comments worth making, but I have to go)

Chew Terr · #3

Hey, just a couple comments since I'm not much stronger.

Edit: Amnal made a review since I started this, so much of this may be redundant.

9: Not big on the kick here, as there's nothing around locally to make it a good option. It's not letting me download the SGF, so I can't make pretty pictures to show how it could turn out. Essentially, however, the kick forces white to stabilize ideally, without actually defending the corner utterly.
11: While it seems interesting when combined with your approach below, it leaves scary aji in the top corner. Normally, F16 is standard here, because otherwise white can start a ruckus with something like (if I recall properly) E16.
27: While this is certainly a good move locally, I prefer C3. It seems pretty huge, as it seems to just work.
31: I like it, because it builds moyo with your wall
37: Forces white to separate your weak groups. P14 looks like a better aggressive option, or you could back off and protect.
101: I may be too aggressive, but I'd say, cut at H13.
122: This is hard, a lot of the things prior were either bigger or urgent. The best chance I can find would be at 94.
136: We're in endgame, so you might want to fit in some of your sente endgame, like C8 and C10.

I hope this helps a bit!

freegame · #4

I downloaded the sgf, but can't open it ("Unterminated property argument on line 2" error)

anyway If I had to point out a single mistake for losing the game it would be move 51:
51: this move does not protect anything and is just floating around in the center. H10 would be much better (it protects your bottem/center teritory)

Bill Spight · #5

A few comments:

Butchering the attack in the top right was very costly. Taking gote made it worse.

Bill Spight · #6

freegame wrote:

I downloaded the sgf, but can't open it ("Unterminated property argument on line 2" error)

anyway If I had to point out a single mistake for losing the game it would be move 51:
51: this move does not protect anything and is just floating around in the center. H10 would be much better (it protects your bottem/center teritory)

may be a bit of an overplay, but I think that the serious damage has already been done with :b45:

-

.

(Not to mention protecting the top left corner.)

I had trouble with the SGF file, too. I just made like I was going to quote it and copied it. That worked.

Joaz Banbeck · #7

Bill Spight wrote:

{in the game comments}*** Your wall is strong, it does not need an extension...

This confuses me. I thought that all walls needed extensions sooner or later. Did you mean to say that it does not need an extension as much as the move is needed elsewhere?

Joaz Banbeck · #8

About kicking ( move 9 at C15 ):

The kick is often misunderstood by beginners as a territorial move. It is not. The 4-4 stone is an influence stone, and theoretically should be used to attack or to facilitate an attack.
When the opponent makes the common 6-3 approach to your 4-4 stone, the purpose of the kick is twofold: 1) To prevent access to easy eye space in the corner with the slide to the 2-4 point, and 2) to make him heavy.

Click Here To Show Diagram Code: [go]$$Bc White is light $$ |------------------ $$ | . . . . . . . . . $$ | . . . . . . . . . $$ | . . . . . . . . . $$ | . . . X . . . . . $$ | . . . . . . . . . $$ | . . W . . . . . . $$ | . . . . . . . . .[/go]

Click Here To Show Diagram Code: [go]$$Bc White is heavy $$ |------------------ $$ | . . . . . . . . . $$ | . . . . . . . . . $$ | . . . . . . . . . $$ | . . . X . . . . . $$ | . . X . . . . . . $$ | . . W W . . . . . $$ | . . . . . . . . .[/go]

Click Here To Show Diagram Code: [go]$$Bc White is starting to make easy life $$ |------------------ $$ | . . . . . . . . . $$ | . . . . . . . . . $$ | . . . . . . . . . $$ | . 2 . X . . . . . $$ | . . . . . . . . . $$ | . . O . . . . . . $$ | . . . . . . . . .[/go]

The down side of this is that once you have kicked, you have encouraged your opponent to build a small wall that partially obstructs the development of your 4-4 stone.

Digression on the development of stones:

Basic 'direction of play' theory says that a 4-4 stone is not a corner stone, that it is oriented toward the middle of the board, or maybe the nearby sides. In the diagram below, the black 4-4 stone wants to have friends at 'a', or maybe 'b'. If all of these are blocked, 'c' is needed.
On a larger scale, the 4-4 stone wants friends around 'd'.

Click Here To Show Diagram Code: [go]$$B Development of a 4-4 stone $$ ----------------------- $$ | . . . . . . . . . . . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . . . b . . . d . . . . . $$ | . . . X . a . . . d . . . . . $$ | . . . . c . . . . . . . . . . $$ | . . b a . . . . . . . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . d d . . . . . , . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . . . . . . . . . . . . .[/go]

If white approaches from one side, black usually takes the other:

Click Here To Show Diagram Code: [go]$$W ( 'a' is often as good as 2 ) $$ ----------------------- $$ | . . . . . . . . . . . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . . . 1 . . . . . . . . . $$ | . . . X . . . . . , . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . a 2 . . . . . . . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . , . . . . . , . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . . . . . . . . . . . . .[/go]

If white gets to approach from both sides, black is unhappy. He must run out to 'b' or 'c'.

Click Here To Show Diagram Code: [go]$$B $$ ----------------------- $$ | . . . . . . . . . . . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . . . O . . . . . . . . . $$ | . . . X . c . . . , . . . . . $$ | . . . . b . . . . . . . . . . $$ | . . . O . . . . . . . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . , . . . . . , . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . . . . . . . . . . . . .[/go]

This black stone is totally ruined:

Click Here To Show Diagram Code: [go]$$B $$ ----------------------- $$ | . . . . . . . . . . . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . . . O . . . . . . . . . $$ | . . . X . . . . . , . . . . . $$ | . . . . . O . . . . . . . . . $$ | . . . O . . . . . . . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . , . . . . . , . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . . . . . . . . . . . . . $$ | . . . . . . . . . . . . . . .[/go]

If the opponent can make the other approach, your 4-4 stone will be compromised.

Click Here To Show Diagram Code: [go]$$Bc Stymied 4-4 stone $$ |------------------ $$ | . . . . . . . . . $$ | . . . . . . . . . $$ | . . . . . . . . . $$ | . . . X W . . . . $$ | . . X . . . . . . $$ | . . O O . . . . . $$ | . . . . . . . . .[/go]

So you almost always play in that area yourself immediately after kicking.

Click Here To Show Diagram Code: [go]$$Bc Good extension to develop the 4-4 stone $$ |------------------ $$ | . . . . . . . . . $$ | . . . . . . . . . $$ | . . . . . . . . . $$ | . . . X . 3 . . . $$ | . . 1 . . . . . . $$ | . . O 2 . . . . . $$ | . . . . . . . . .[/go]

This allows your opponent time to reinforce his newly-made-heavy group by means of a three-space extension ( following the principle of N+1 spaces from a wall that is N stones long )

Click Here To Show Diagram Code: [go]$$Bc Too comfy for white. \nBlack will have a difficult invasion at 'a'.\nBut white can still invade at 'b'. $$ |------------------ $$ | . . . . . . . . . $$ | . . . . . . . . . $$ | . . b . . . . . . $$ | . . . X . 3 . . . $$ | . . 1 . . . . . . $$ | . . O 2 . . . . . $$ | . . . . . . . . . $$ | . . a . . . . . . $$ | . . . . . . . . . $$ | . . . 4 . . . . . $$ | . . . . . . . . . $$ | . . . . . . . . .[/go]

It follows, then, that you usually kick ONLY when you have some means of preventing an extension from his newly-created wall.

Click Here To Show Diagram Code: [go]$$Bc White is cramped if marked stone is there before the kick $$ |------------------ $$ | . . . . . . . . . $$ | . . . . . . . . . $$ | . . . . . . . . . $$ | . . . X . 3 . . . $$ | . . 1 . . . . . . $$ | . . O 2 . . . . . $$ | . . . . . . . . . $$ | . . . 4 . . . . . $$ | . . . . . . . . . $$ | . . . B . . . . . $$ | . . . . . . . . . $$ | . . . . . . . . .[/go]

Click Here To Show Diagram Code: [go]$$Bc Also White is cramped if this marked stone is there before the kick $$ |------------------ $$ | . . . . . . . . . $$ | . . . . . . . . . $$ | . . . . . . . . . $$ | . . . X . B . . . $$ | . . 1 . . . . . . $$ | . . O 2 . . . . . $$ | . . . . . . . . . $$ | . . . . . . . . . $$ | . . . 3 . . . . . $$ | . . . , . . . . . $$ | . . . . . . . . . $$ | . . . . . . . . .[/go]

Bill Spight · #9

Joaz Banbeck wrote:

Bill Spight wrote:

{in the game comments}*** Your wall is strong, it does not need an extension...

This confuses me. I thought that all walls needed extensions sooner or later. Did you mean to say that it does not need an extension as much as the move is needed elsewhere?

I sense that we may be using language in slightly different ways. Rather than delve into that, let me say that Takagawa said that there are two kinds of walls, those that need an extension, and those that do not. (OC, there is a certain fuzziness to that distinction, IMO.) Walls that have eye potential do not need an extension, while walls without eye potential need an extension to make a base and provide eye potential. I think of it more as that a strong wall does not need an extension.

As usual, I think that examples are better than verbal explanations. Here are three example games from the 18th century. (I like to use those ancient games because players were more territorial than modern pros, but still understood thickness very well.

These games also illustrate the dictum about not making territory from thickness.)

Enjoy!

Kirby · **#10**

Bill Spight wrote:

...Walls that have eye potential do not need an extension, while walls without eye potential need an extension to make a base and provide eye potential. I think of it more as that a strong wall does not need an extension.
...

If this is true, I can see some rationale to the principle: if a wall is strong and you do not have to worry about its health, you can try to find a way to use it later, so an extension may not be necessary.

But this leaves me with the question, "How can you use a wall that has no extension, and turn it into points?".

Like in the last game, if white had played around D13 at some point, black would not have gotten many points from his wall. In the game, black could play on the left first, but there was no guarantee of getting points... Seems risky without the guarantee of points.

Dusk Eagle · **#11**

The point is to make points / take away points in areas not immediately in front of the wall. It matters little if you end up with any points at all in front of your wall. As long as you are able to utilize it effectively in fighting, it has done it's job. See, for example, the video commentary of this game: http://www.gocommentary.com/free-videos ... nyuan.html. White does far more with his wall than make points in front of it.

Also, in the last of the games Bill posted, let's say White did play around D13. So what? The corner is still a cinch to invade. Black can then extend along the top side to whatever point he deems best (including a shimari in the top-right) as, in order for white to play at D13, the top-right joseki cannot have occurred. Even if black chooses a simple shimari, white will still struggle to claim the corner territory, as E16 is a fourth-line stone and D13 does not help protect the corner at all. For white to spend an entire move to only partially erase your potential while not claiming all that much for himself is not exactly a huge success story for him.

Bill Spight · **#12**

Kirby wrote:

Bill Spight wrote:

...Walls that have eye potential do not need an extension, while walls without eye potential need an extension to make a base and provide eye potential. I think of it more as that a strong wall does not need an extension.
...

If this is true, I can see some rationale to the principle: if a wall is strong and you do not have to worry about its health, you can try to find a way to use it later, so an extension may not be necessary.

But this leaves me with the question, "How can you use a wall that has no extension, and turn it into points?".

Takagawa said that it is almost impossible to make (solid) territory, that territory gets made (solidified) through fighting. Now, the usual answer about how thickness becomes territory is through fighting. But that is not the only way. Books have been written about this.

Quote:

Like in the last game, if white had played around D13 at some point, black would not have gotten many points from his wall. In the game, black could play on the left first, but there was no guarantee of getting points... Seems risky without the guarantee of points.

Your assertion about a White play around D-13 is unproven. It is possible that Black could end up with nothing to show from his wall, but White cannot simply defeat the wall by preventing an extension if the wall needs no extension.

One reason I chose this game is that it is fairly easy to see territory that Black makes from that wall. Did you miss it? Consider move 51. That is a rather unusual approach, isn't it? (Just looking at the top half of the board, the usual play is to come in at the 3-3.) And what about White's reply? White did not secure the corner, did he? Why? Because of Black's wall. White did not want to let Black make a moyo on the left side. Instead he let Black into the corner and extended his own moyo. So the obvious place that Black made territory from the wall is in the top left corner. (The wall was useful in later fighting, as well.)

Now, there are games where it is not all that obvious how a wall is utilized. This game could have developed in such a way. For instance, instead of approaching the top right corner, White could have enclosed the top left corner, and then, after Black enclosed the top right corner, White could have extended towards the wall, allowing Black to play first on the top side. Later fighting might not have made much use of the wall.

Sentetsu did not play that way. Why not? Because those plays were inferior. The White extension to C-13 or D-13 is inferior, because of the wall. The wall limits the development of White on the left side, just by being there. A play on the top side at that point would be better. Why is the enclosure in the top left corner inferior to the approach to the top right corner? Well, aside from the presence of the other Black wall on the right, because it faces the strong Black wall on the left side, and its natural extension is towards the wall. But, as we have seen, that extension is inferior. Therefore, the wall hinders the development of the enclosure, as well. As John Fairbairn has pointed out, mistakes may carry their own punishment. Sentetsu played well to approach the top right corner and stake out the top side.

Had Sentetsu enclosed the top left corner and then extended towards the wall, so that Black ended up with territory in the top right corner and top side, then we could say, and should say, that Black made territory from the wall in those regions. But that is far from obvious.

Numsgil · **#13**

In the second game, the wall that gets built in the top right... Why doesn't it need an extension after move 18? It looks pretty flat and eyeless to me, and if this were my game I'd make an extension, pat myself on the back for playing well, and not think anything of it. It's not immediately in danger, but if there's a wall that can get in to trouble later I would guess it's a flat wall facing a side and is undercut from below.

Bill Spight · **#14**

Numsgil wrote:

In the second game, the wall that gets built in the top right... Why doesn't it need an extension after move 18? It looks pretty flat and eyeless to me, and if this were my game I'd make an extension, pat myself on the back for playing well, and not think anything of it. It's not immediately in danger, but if there's a wall that can get in to trouble later I would guess it's a flat wall facing a side and is undercut from below.

Click Here To Show Diagram Code: [go]$$Wcm10 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . 4 . . . | $$ | . . . O . . W . . . . . . . 3 2 . . . | $$ | . . . , . . . . . , . . . . 1 , . . . | $$ | . . X . . . . . . . . . . . 7 6 X . . | $$ | . . . . . . . . . . . . . . 5 . . . . | $$ | . . . . . . . . . . . . . . . 8 . . . | $$ | . . . . . . . . . . . . . 9 . 0 . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . X , X . . | $$ | . . . O . . . . . O . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

=

Kono's plan is ingenious. An immediate extension from the top left corner would allow a Black enclosure in the top right, while one after :w12:

, would allow a Black pincer against :w10:

and

. Instead, White builds a strong wall in the top right, at the expense of some territory. This wall works well with the extension from the top left corner, :w20:

. While the wall does not need an extension, White would not want a Black pincer against the White stone in the top left.

As for the strength of the wall, it is 6 stones long. In length is strength. Black has a peep, but no easy attack. Also, the placement of :w18:

is flexible, even after :b19:

. It is the kind of play that you do not let get away. White had it in mind with :w14:

.

Is it possible for the wall to die? Of course. But that would not necessarily be bad. I recall losing -- err, sacrificing -- three walls in one game. My opponent was mystified to find that he had lost.

W+18.5 How does black get it back?

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