How is this position considered even?

[negapesuo]

*assume all other corners are taken by the first 3 moves

I saw this joseki in josekipedia and I'm confused by the comment. It states that the position is even, but I don't see what white has gained from this. It is white's turn now but white still needs a move back in the corner to live right? It has no territory while black has stones on both sides.

Especially consider if black has a stone in the top left side (since white is the one that approached, D16?). I guess white can try to attack the M17 stone... I just have a hard time seeing how this position is not better for black.

Can someone tell me what white would try to do with this group? Thanks.

[EdLee]

- was here first. As shown, has one more stone (5) locally than (4) ;
- we have no idea about the rest of the board ; that's always been a caveat for josekis ;
- AlphaGo, etc. already showed us over 2 years ago many pro evaluations of "josekis" were wrong ( many were also "correct", locally ) ;
- it's always about the whole board evaluation ;
- what to do with ( and ! ) always depends on the whole board ;

assume all other corners are taken by the first 3 moves

Insufficient information to evaluate: we need the whole board, the exact position of every stone ; then we can ask Leela, etc.
- for to live is but only one factor to consider for ; all the factors depend on the whole board ;

Confession, a la Bill's style:
Some years ago I asked a similar question, for a similar shape,
"What is doing ?" Reply, "The stones have their value, even if they don't appear to be doing anything. Also, it depends on the whole board."

[Bill Spight]

Obviously, this position is better for Black, because Black has one more stone than White. The question is, is it better for Black than the original 3-4 stone?

IMO, on an empty board it is slightly better for Black than that. In part because of the concentration of White stones, in part because the Black pincer stone is so far away from the White strength.

But, in fact, this is typical of pincer josekis. All we can ask from a joseki is rough equity.

Once upon a time, a few centuries ago, it was popular among top players to start with a 3-4 by Black, an approach by White, and a pincer by Black. Then White played somewhere else. Already they knew that for White to continue in the same corner was normally suboptimal. Sure, they had joseki for when White did continue, but those joseki typically favored Black, so White did not continue. So here is a joseki where White continues and the result favors Black. Nothing new here, folks.

[ez4u]

White tenukis elsewhere, Black and White exchange for below. How does Black kill White?

$$B
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . O 2 |
$$ | . . . . . . . . . . . X . . . O O X . |
$$ | . . . , . . . . . , . . . . O , X 1 . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$B
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . O 2 |
$$ | . . . . . . . . . . . X . . . O O X . |
$$ | . . . , . . . . . , . . . . O , X 1 . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

PS: I cannot agree with Bill here. White is clearly better here. Black's plays do not work together. This can't be joseki!

[EdLee]

Hi Dave,

White tenukis elsewhere, Black and White exchange for below. How does Black kill White?

Too crude, perhaps ?

$$B
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . 9 . 0 . . . |
$$ | . . . . . . . . . . . . 7 4 3 6 . O 2 |
$$ | . . . . . . . . . . . X . 5 8 O O X . |
$$ | . . . , . . . . . , . . . . O , X 1 . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . , . . . . . , . . . . . , . . . |

Click Here To Show Diagram Code

[go]$$B
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . 9 . 0 . . . |
$$ | . . . . . . . . . . . . 7 4 3 6 . O 2 |
$$ | . . . . . . . . . . . X . 5 8 O O X . |
$$ | . . . , . . . . . , . . . . O , X 1 . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . , . . . . . , . . . . . , . . . |[/go]

( is not even boxed in yet. )

[ez4u]

@Ed - No need to strengthen Black by sacrificing 4. Simply 6 is enough since it threatens to capture 3, no?

[EdLee]

Hi Dave,

Thanks.

$$B
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . 6 . . . |
$$ | . . . . . . . . . . . . . . 3 4 . O 2 |
$$ | . . . . . . . . . . . X . 5 . O O X . |
$$ | . . . , . . . . . , . . . . O , X 1 . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . , . . . . . , . . . . . , . . . |

Click Here To Show Diagram Code

[go]$$B
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . 6 . . . |
$$ | . . . . . . . . . . . . . . 3 4 . O 2 |
$$ | . . . . . . . . . . . X . 5 . O O X . |
$$ | . . . , . . . . . , . . . . O , X 1 . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . , . . . . . , . . . . . , . . . |[/go]

( Miai of and get out. )

[RobertJasiek]

The stone difference is 1 (Black has played 1 local excess play).

The territory count is 1 using the concept of current territory and, for only this purpose and counting White's current territory, assuming Black S16 - White N18 etc (not Black S16 - White T18).

The influence stone difference is 2 (3 black and 1 white influence stones).

Adjusting the stone difference 1 becoming the stone difference 0 and accounting 1 extra white influence stone elsewhere, we get the adjusted influence stone difference 1.

With the territory count 1 and the adjusted influence stone difference 1, the local position belongs to the value type "small values", i.e., values that are almost 0. This value type indicates a locally almost equal position, i.e., we can call it a joseki. Global considerations dominate.

[John Fairbairn]

Where is the evidence that this is joseki?

The position shown occurs just twice in the GoGoD database and in neither case was a pincer involved. The stone at M17 is played after the rest of the moves, and as a check (tsume), not as a pincer. The check is also played deep into the middle game with many stones close by. In neither case is the position remarked on in the accompanying commentaries in the sources.

M17 as an initial pincer is relatively uncommon in itself (though somewhat fashionable since 2000) but, when it does occur, a White attachment at the 3-3 point is rare (7 cases - which seems to suggest that White doesn't like how that might end up, e.g. as here?).

I think it's worth also thinking about what we mean by the word "even." It's true that (assuming Japanese sources - the most common) gokaku is glossed as "even" in dictionaries, but in go it seems to have its own nuance and could probably be rendered better as "mutually acceptable." This is mainly because the tag is applied so often to cases where one side has an extra stone, as here, but the fact that gokaku is used almost exclusively in go despite the existence of other possible ways of saying even (e.g. gobu) suggests that it is seen as a technical word, i.e. has the restricted meaning I have indicated.

[Uberdude]

That is a very weird pincer, if played as such. Did crop up in an AlphaGo self-play game with the Kobayashi opening though, and Redmond commented on the unusualness: https://youtu.be/TepPAXrz3-Q?t=4m28s.

[Gomoto]

Tried this is in some different board configurations with Leela Zero.

White is way better everytime.

But black surly has another way to play. Why should he play like this?

[Bill Spight]

Where is the evidence that this is joseki?

The position shown occurs just twice in the GoGoD database and in neither case was a pincer involved.

Yeah, I just accepted the idea that it was joseki without checking. Mea culpa!

[Bill Spight]

Tried this is in some different board configurations with Leela Zero.

White is way better everytime.

How does this position compare with the single stone on the 3-4 pt.? (Top bots give the advantage to White, given the 7.5 komi.) Thanks.

[BlindGroup]

Does it matter that white retains sente after this sequence?

My initial reaction to this position was that it seems like black has allowed white to settle in the corner in exchange for a slightly larger settled position on the right. In exchange, white gets sente and the vulnerable pincer stone. Black either needs to make a gote move to settle that stone or white can come back later and harass it. Given how much sente is supposed to be worth in the fuseki, that seems like adequate compensation for black's slightly larger position on the right.

In The 21st Century Dictionary of Basic Joseki, Shinji describes the following position as equal:

$$W
$$ ------------------------+
$$ . . . . . . . . . . . . |
$$ . . . . . . . 5 . . . . |
$$ . . 6 . . X . . . 1 7 . |
$$ . . , . . . . O 3 X 4 . |
$$ . . . . . . . . . . . . |
$$ . . . . . . . . . . . . |
$$ . . . . . . . . . 2 . . |
$$ . . . . . . . . . . . . |
$$ . . . . . . . . . . . . |
$$ . . , . . . . . , 8 . . |
$$ . . . . . . . . . . . . |
$$ . . . . . . . . . . . . |

Click Here To Show Diagram Code

[go]$$W
$$ ------------------------+
$$ . . . . . . . . . . . . |
$$ . . . . . . . 5 . . . . |
$$ . . 6 . . X . . . 1 7 . |
$$ . . , . . . . O 3 X 4 . |
$$ . . . . . . . . . . . . |
$$ . . . . . . . . . . . . |
$$ . . . . . . . . . 2 . . |
$$ . . . . . . . . . . . . |
$$ . . . . . . . . . . . . |
$$ . . , . . . . . , 8 . . |
$$ . . . . . . . . . . . . |
$$ . . . . . . . . . . . . |[/go]

In this position, black seems even better off than in OP's example because black now has settled positions on the top and the right. Shinji just declares this position equal without explanation, but my interpretation has always been that white retaining sente is the compensation for black's territorial advantage.

[Bill Spight]

Does it matter that white retains sente after this sequence?

The net number of stones matters. In both cases Black has one extra stone. For equity, early in the game Black should have around 14 pts. more than White, including pts. for influence. At the end of the game one extra stone may not be worth any territory at all.