Endgame Clamp

  Difficulty: Intermediate   Keywords: EndGame, Tesuji

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The Endgame Clamp - Conventional wisdom

This part of the page follows the lines of most endgame presentations, as e.g. in Ogawa/Davies: The Endgame. A more thorough discussion here at The clamp is gote

result (B5-W8 later sente follow up)  
the monkey jump is inferior  

a and b are two point gote plays for either white or black.

averaging out...  

so the monkey jump is two points inferior on average than the endgame clamp


W4 Variation  

How about this W4 ? DieterVerhofstadt


One point better for Black, but White has sente. But of course, if Black leaves B7-W8-B9 unplayed, then he can come back to take two points in gote endgame later.

Counting value  

unkx80: I shall count the value of the sequence up to W6, assuming that the territories are defined by the marked stones.

Comparing it with the endgame clamp diagram, White has one extra point of territory but Black has captured one more stone than White.

The value of W4 in this variation is the same as the one shown in the endgame clamp diagram. :)

BillSpight: Indeed that is so. It might be interesting to compare it with the solid connection in a DifferenceGame: ClampConnectionComparison.

Variation 2

Overdoing it.  

It's interesting to note that this B1, which seems more severe, is one point worse, and loses sente!

Same result.  

Black pushing at W4, instead of B3, is one more point worse off (If I've read correctly).


DieterVerhofstadt writes: Morten, this is called synchronicity. I was about to make exactly the same comment !

Another way ?  

Either Black has sente or there is an extra reduction at a, resulting in a large ko for both or another loss for White.

But ...  

But White sacrifices a stone. Again: same result, one point worse off and loss of sente.


The sad thing is that I would play this (and similar non-optimal moves) if this were a real-game situation.... The temptation to play something which looks bigger to begin with , although I have a nagging feeling from having seen it in a book or in a game that it is inferior.... is often too big :o(( --MortenPahle

The clamp is gote

BillSpight: Looks can deceive. The clamp is gote.

unkx80: You are not wrong, but you have to take into account the actual situation. Most Chinese Go books written by professional players say that the clamp is sente.

Bill: Most Japanese go books do, too. ;-)


The clamp is sente if it is played in the diagram "Using the endgame clamp 001/002" [1]

The clamp is gote if it is played in the diagram "W4 Variation" [2]

The above is based on an assumption that both parties complete all sequence of play.

If playing elsewere is considered, then no one knows who can get sente (at lease in theory). It is because even B1 can be ignored if W can find a bigger value elsewhere to offset the loss of not responding to B1.

Bill: aLegendWai, you are using the terms, sente and gote in a different sense than they are used on the rest of this page. When we say that a play or position is sente or gote, without reference to other plays, we are using the sense used in evaluating positions and plays. In that sense, the clamp, B1 - B3, is gote.

There is theory behind this usage, and because of that theory we can predict that correct play will usually be gote for this position.


W2 protects the corner. That reduces the local temperature. White should view the marked stones lightly. Later B5 is sente.
Later the following is Black's sente.


B1 is tesuji. If Black starts with B3, he loses sente.

still gote  

MartijnWallage?, 1k: Well, if sente is so important. White can play W2 and then B3 is not sente any more.
But sente can't be so important since in the "Sente" diagram Black doesn't gain anything.

Bill: Indeed, after B1 - W2, B3 is not sente. In fact, it is an ambiguous move. For evaluation purposes we can treat it as White's sente.

Still sente  

B3 elsewhere.
If we compare this with the sente diagram, we see that White is 2/3 of a point worse off here, and B1 - W2 is still sente.

As for a sente not gaining anything (on average), that is the nature of a sente-gote position: sente gains nothing.

How large is the sente?

Reverse sente  

If White plays the reverse sente at W1, now a and b are miai. This position is 2 1/3 point better for White than if Black takes his sente, so the sente is worth 2 1/3 points.
If Black plays gote he picks up only 1 2/3 points.

So if Black does not play his sente, White will play the reverse sente (as a rule). If the ambient temperature is less than 2 1/3, that represents a loss for Black.


tapir: If it ends in gote after the drop in temperatur (with the defending players answer) - is the clamp really better than the monkey jump - which is at least sente? isn't it usually a sequence to be considered en bloque only when temperature temporarily increases during the sequence?

Bill: The monkey jump is a losing sente. It loses 2/3 of a point, on average. On rare occasions it is right, of course. :)


Semper: Quote from Unkx80:

"=== Variation 2

Overdoing it.  

It's interesting to note that this B1, which seems more severe, is one point worse, and loses sente! "

In both the follow up you played the 3 at either a or b. Why not keep it simple and play using the tesuji:

Variation 2

Overdoing it ?  

You'll notice black still has sente. 1 point can be worth still having that, and I didn't quite get that part about playing at b instead of 1. I mean I did, but not how it is worth more.

Overdoing it ?  

fractic: White can throw-in at W1 to set up a connect and die

Endgame Clamp last edited by PJTraill on February 10, 2019 - 18:08
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