Tedomari

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    Keywords: EndGame, Strategy, Go term

Tedomari means the last play. It is used not only for the last play of the game, but for the last play at different stages, and for the last play before the size of plays (temperature) makes a significant drop. As a general rule you want to try to get tedomari. There is a saying about the last gainful play of the game, Tedomari is worth double.

Getting tedomari is related to go infinitesimals and how to play them.

--BillSpight

About getting the last play Tedomari

Charles Matthews When it's down to mutual damage, you can call it 'who blinks first'. If after some plays each advancing into the opponents' territory, Black has a threat worth t and White has a threat worth t', Black hopes t is worth noticeably more than t'.

Then if it's White's turn, she can choose between (a) stop Black's threat, and so Black's play stopping White's threat gets tedomari, or (b) play the move setting up the threat but allow Black's threat too - White carrying out the threat is tedomari all right but White has already lost too much.

See more in /Discussion.


Tedomari problems

(sig) A neat "6 dan" [ext] tedomari problem @ goproblems. [1001]


Here is a simple tedomari problem I (Bill Spight) composed.

[Diagram]

Tedomari problem 1

How large are the plays, a, b, and c?
What is the optimal order of play when Black plays first, and what is the result?
What is the optimal order of play when White plays first, and what is the result?

(The optimal order of play obtains the best result for each player.)

/Solution 1


A very nice example of tedomari that you can work out yourself are the problems [ext] 365 and [ext] 368 at goproblems.com.

--dnerra

Bill: They are from Mathematical Go.
Andy: Also quite instructive: [ext] 3104

Bill: Thanks, Andy. :-) However, that is not really a tedomari problem. See Numbers.

Can you explain the distinction?

Bill: Sure. The point of the numbers problem is making the largest play.

[Diagram]

Numbers (Right)

Here Black plays correctly and holds White to 6 points. Black also gets tedomari.

[Diagram]

Numbers (Wrong)

Here Black plays incorrectly and lets White get 7 points. However, Black still gets tedomari.


Robert Pauli: Here's a cute little tedomari example (DGoZ 5/03):

[Diagram]

White's turn. No komi. No captives.

Locally best play isn't globally best play, as everyone will find out sooner or later.



I like these miai values (even if I'm still struggling with them), however, would they help White in any way ??

Bill: Gee, maybe I am missing something, but the best local play seems like the best global play to me. (OIC. It depends on what you mean by best play. I think you mean optimal play. I had orthodox play in mind. The normally best local play differs from the best global play at or below temperature 1. They are the same above that.)

Robert Pauli:
Hmm, I'm ahead of the solution in DGoZ 6/03, but...

[Diagram]

White wins by one[1]

[Diagram]

Only jigo

Locally best for the lower part, but missing the win.



Are you using some kind of mathematical never-ever-draw rules, Bill, or what am now I missing? ;-)

So, how do miai values direct White to choose the "inferior" move?

Bill: Here is what I mean:

[Diagram]

Normal local play

After W1, White has W3 - B6 with sente, and Black has B8 - W9 with sente. This is 2 points better than the result above, starting with W8. With rare exceptions, W should play W1 unless the remaining plays are very small.

(W3 - W5 is sente because of possible later threats against Black's group. But even if it is a 2 2/3 point gote instead of a 3 point sente, W1 is still the normal local play.)

W1 was my first thought, and then I wondered why this was a problem. ;-)


[1]

[Diagram]

Better play for Black

Bill: A fine point: B2 is better technique than playing the sente at B8 first, because it gives White the chance to make a mistake.

[Diagram]

White's mistake

If White makes a mistake and plays W5, Black gets tedomari, for jigo.


Tedomari in the opening

Bob McGuigan: Tedomari applies in other stages of the game, as Bill mentions at the start of this page, but no examples are given. Here is one from the fuseki. The following position is Black to play and is from the book Jobansen Kono Itte by Fujisawa Shuuko:

[Diagram]

Black to play

Shuuko says that the correct move for Black is at the circled point, which one could call tedomari and the only move.

[Diagram]

Tedomari example 2

If White adopts a mimic go strategy, Black can take the last oba by playing move 11 at a (tengen).


Further discussion on /Discussion page.


[1001]

Bill: The original problem had a flaw where a position that looked like a go infinitesimal favoring White was actually a zero, because of damezumari.

Truc: Oops, I overlooked the damezumari. Updated the problem at goproblems.com, now it should be working as intended.

Bill: Yes, I think it is an excellent problem! :-) (I removed the spoiler above.)


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This is a copy of the living page "Tedomari" at Sensei's Library.
(OC) 2005 the Authors, published under the OpenContent License V1.0.
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