Nature of tesuji?

General conversations about Go belong here.
Kirby
Honinbo
Posts: 9553
Joined: Wed Feb 24, 2010 6:04 pm
GD Posts: 0
KGS: Kirby
Tygem: 커비라고해
Has thanked: 1583 times
Been thanked: 1707 times

Re: Nature of tesuji?

Post by Kirby »

Toge wrote:
Kirby wrote:The point is to play the best move. This may or may not be a tesuji.


- This truism won't help in actually finding the best move. People read tesuji books because they want to improve their game. Which move would you play in examples listed in OP?


I don't think there exists a "silver bullet", like you seek. The answer is always to read and evaluate.

Here are some ideas of how I might think:


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


Above, let's say black plays "a" and white plays "c".
Black may decide to tenuki, but if he does and white later captures the black stone, white gains a point. If black plays "b" immediately, and white does "c", if black does tenuki, white playing "a" doesn't give an extra point.

On the other hand, if black plays "b", white may be less inclined to even answer than if black plays "a".

So instead of trying to develop an always working heuristic, I think it's better to consider the implications of each move, given the entire board.


Click Here To Show Diagram Code
[go]$$B 
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | X X X . . . . . .
$$ | O O X . X . . . .
$$ | . . O X . . . . .
$$ | O O . O X X X . .
$$ | . . . O X O O X .
$$ | . . . 2 O 1 a b .
$$ ------------------[/go]


Both have goods and bads. Suppose you want to preserve ko threats. Taking the stones off the board removes the ko threat white has of saving the stones. I this sense, "a" may be better.

But suppose that there is a weak black group to the right of this, and playing "b" will allow you to connect. In that sense, "b" could be better.

Click Here To Show Diagram Code
[go]$$B
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | X X X . . . . . .
$$ | O O X . X . . . .
$$ | . . O X . . . . .
$$ | O O . O X X X . .
$$ | . . . O X O O X .
$$ | . . . c O 1 b d .
$$ ------------------[/go]


As white, I'd usually connect at "c". If I play "b", black gets "d" for free, and I still have to connect at "c" after he captures, anyway...

BUT, let's say the position was ignored for awhile, and now it is ko somewhere on the board. Playing "b" gives me more ko threats.


Click Here To Show Diagram Code
[go]$$W 
$$ | . . . . . . . O .
$$ | . . O O O . . . .
$$ | . . . . . . O . .
$$ | X X X 1 b . . . .
$$ | O O X a X . . . .
$$ | . . O X . . . . .
$$ | O O . O X X X . .
$$ | . . . O X O O X .
$$ | . . . . O O . . .
$$ ------------------[/go]


"a" could be good for giving white less ko threats, and "b" could be good for taking away white eyespace, for example...


So basically, go is too complicated to have always working heuristics like this. That's why reading and evaluation are important.

It is great to study tesuji - it gives you great ideas on possibilitiea you could do... But you should still play the move you think works best with the current board position, whether or not it is in a tesuji book.
be immersed
User avatar
karaklis
Lives in sente
Posts: 797
Joined: Tue Apr 20, 2010 2:14 pm
GD Posts: 600
Has thanked: 93 times
Been thanked: 105 times

Re: Nature of tesuji?

Post by karaklis »

I have always thought of tesuji as local moves, except if kos or ladders are involved. It is always used to achieve something local, e.g. connect/save own stones, cut/capture the opponent's stones. And the type of move deviates from trivial/shape moves, so it's a move that has to be learned beside the "normal" moves.
User avatar
Sverre
Lives with ko
Posts: 193
Joined: Thu Apr 22, 2010 1:04 pm
Rank: 2d EGF and KGS
GD Posts: 1005
Universal go server handle: sverre
Location: Trondheim, Norway
Has thanked: 76 times
Been thanked: 29 times

Re: Nature of tesuji?

Post by Sverre »

Kirby wrote:Here are some ideas of how I might think:


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


Above, let's say black plays "a" and white plays "c".
Black may decide to tenuki, but if he does and white later captures the black stone, white gains a point. If black plays "b" immediately, and white does "c", if black does tenuki, white playing "a" doesn't give an extra point.

On the other hand, if black plays "b", white may be less inclined to even answer than if black plays "a".

So instead of trying to develop an always working heuristic, I think it's better to consider the implications of each move, given the entire board.


Click Here To Show Diagram Code
[go]$$B
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | X X X . . . . . .
$$ | O O X . X . . . .
$$ | . . O X . . . . .
$$ | O O . O X X X . .
$$ | . . . O X Q Q X 6
$$ | . . . 2 O 4 1 . .
$$ ------------------[/go]


If Black plays 'b' then White 4 is almost sente, as it threatens the attachment at 6 (or cutting). I think this fact is worth more than the potential single point in most positions.
Kirby
Honinbo
Posts: 9553
Joined: Wed Feb 24, 2010 6:04 pm
GD Posts: 0
KGS: Kirby
Tygem: 커비라고해
Has thanked: 1583 times
Been thanked: 1707 times

Re: Nature of tesuji?

Post by Kirby »

Sverre wrote:
Kirby wrote:Here are some ideas of how I might think:


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


Above, let's say black plays "a" and white plays "c".
Black may decide to tenuki, but if he does and white later captures the black stone, white gains a point. If black plays "b" immediately, and white does "c", if black does tenuki, white playing "a" doesn't give an extra point.

On the other hand, if black plays "b", white may be less inclined to even answer than if black plays "a".

So instead of trying to develop an always working heuristic, I think it's better to consider the implications of each move, given the entire board.


Click Here To Show Diagram Code
[go]$$B
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | X X X . . . . . .
$$ | O O X . X . . . .
$$ | . . O X . . . . .
$$ | O O . O X X X . .
$$ | . . . O X Q Q X 6
$$ | . . . 2 O 4 1 . .
$$ ------------------[/go]


If Black plays 'b' then White 4 is almost sente, as it threatens the attachment at 6 (or cutting). I think this fact is worth more than the potential single point in most positions.


It could very well be, and it is a good aspect to consider. My point is just that relying upon whether something is considered as a "classic tesuji" or not is not sufficient for playing the best move. Considering possible consequences of a particular move, like you've done here, is important for having a good strategy.
be immersed
FlameBlade
Dies in gote
Posts: 51
Joined: Wed Apr 21, 2010 6:08 pm
Rank: 4d
GD Posts: 262
Has thanked: 25 times
Been thanked: 5 times

Re: Nature of tesuji?

Post by FlameBlade »

Which move perceived as a tesuji depends on a player's strength. To 30k, Crane's nest is impressive, but to a dan player, it's an ordinary move that they know by heart.
Post Reply