Kikashi
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Kikashi, a Japanese go term adopted into English, is a sente move that produces a certain additional effect. Because it has done its work, it can normally be freely abandoned unless it is part of a much larger chain or group. It is usually translated as forcing move.
A kikashi stone is a stone played with kikashi. In many cases, kikashi stones may be viewed lightly. Such a kikashi stone has done its work by evoking a response and are easy to throw away. In other words, kikashi stones often are disposable stones.
There has been a lively kikashi sente discussion which showed the necessity to quote from literature how we should understand the concept of kikashi. See also forcing move misunderstandings.
Quotes from well-known authors
From Attack and Defense by James Davies and Ishida Akira: A forcing move may be defined as a sente move that brings its player some potential advantage without having to be followed up or defended.
From Strategic concepts of Go by Nagahara Yoshiaki and Richard Bozulich: A kikashi is a forcing move played to produce an effect. That is, a kikashi is a play which must be answered, usually in just one way, the exchange of the kikashi and the answer being useful in some way to the player of the kikashi. The terms kikashi and sente may seem to have the same meaning, but kikashi is applied to moves which are more or less incidental to the main flow of play. Once played, kikashi stones can typically be abandoned without any great loss.
Rob van Zeijst in his column The Magic of Go: For an amateur, it is often hard to determine whether a move is a kikashi or a waste of potential. The average player will decide that a move is a kikashi if it is answered, as this will indicate that he has kept sente (initiative). There is no simple description for a kikashi. If in doubt, follow this rule of the thumb: A kikashi has outside significance while the answer to it usually has no or little value.
This appears to mirror the idea given about kikashi in Attack and Defense, incidentally: the only proviso is whether the outside significance creates more aji than the use of the forcing move dissipates.
Sakata, in the Sakata no Go series, vol. 5, How to Sacrifice Stones, p. 1, says this about kikashi:
Sente is certainly a condition of kikashi, but it is not the case that every play that is sente is also kikashi. If we compare the value of my play to the value of the opponent's response, only when my play does more work does it become kikashi. Accordingly, the value of kikashi, unlike that of plays in other situations, cannot be reckoned as so many points. On the one hand, the work done may be worth a mere fraction of a single point; on the other hand, a kikashi stone may later come to play a decisive role in winning or losing the game. In any event it is a subtle matter.
We professionals exercise a good deal of sensitivity in regard to kikashi. Often in game post mortems the question of whether a certain play is really kikashi or not becomes the subject of debate.[1]
-- Slightly polished translation by Bill Spight.
Part of the discussion was about the semantics of kikashi. The other part considered the relation with aji-keshi, sente and thank-you move. Consensus yielded:
The main point is that kikashi are sente and
- aren't to be criticised for bad aji keshi
- don't require defensive plays afterwards, so are light not heavy.
Otherwise forcing plays can be a mistake.
Examples
Before living with , White makes a kikashi with
. This is an example of the proverb play kikashi before living. This serves as a peep at the Black's tiger shape, forcing Black to answer at
. It also has a local achievement too: by connecting the
stone in sente, it enhances the strength of the White wall. As
is part of the White's wall, the proverb on sacrificing kikashi stones does not apply in this example.
Later, the peep at is another typical example of a kikashi. Due to his marked tiger shape, White is already connected, and there is hardly any aji left in this position. So Black's move is justified: he forces White to confirm the choice she already made: connect her stones.
does several things at a time: it destroys some eye shape, and it can serve as a ladder breaker later, or be a stone that is just in the right spot to win a capturing race. But
is a stone to be treated lightly. It is not an important stone. It is a kikashi stone.
Enfors: Let me see if I get understand this properly. The point of is not to make white play at
. The point of playing
there is that it might become useful in the future, and it is the fact that
forces white to play at
which enables black to play at
without losing sente. Correct?
Phelan: Correct. :)
Suppose White is ahead in territory but Black has more influence. With and
, White forces Black to take some territory at the top. After his submissive answers, she jumps to
. Her stones
,
and
, will have some influence on the proceedings in the center. If Black makes an attempt to capture
and
, they should be sacrificed in order to strengthen
.
Bill:
looks peculiar, doesn't it? Don't we have any good examples from pro games?
Dave: With
, White pulls out the stones played earlier - this is not kikashi. Compare this example from the 7th Honinbo title match. Black plays kikashi with a similar shoulder hit and then abandons the kikashi stones in order to invade the corner.
Bill: Great example, Dave! :)
JohnMoser: I have to agree with Dave. The area marked .C seems to represent territory dispute. This could be destroyed territory (stones there, adds to no one's score) or captured territory (surrounded). If white captures
and
, it can gain those territory as score; if Black connects
and
to
and fails to form territory in that area, White still fails to gain territory from the exchange as well.
and
could be worth 5 or 10 points.
Dave: Later in the game White starts to play against the kikashi stones but both players treat them lightly. With
Black is willing to let White cut off the two stones. However,
shows that White has no interest in such a small-scale capture.
Disposability as middle-game Joseki
In this position, Black has a few forcing moves. He starts off with . If unanswered, White's position would completely crumble.
then forces White to take the two stones. White may decide (but is unlikely) to abandon her three stones, depending on the rest of the top side. Next,
forces once more to effectively take the stones off the board. Next, Black can play along the left side or connect around a.
and
are mere sente moves, moves that are played to keep the initiative while building the position.
is the only example of kikashi, because the stone is treated as disposable:
Later, close to the endgame, this may be played. The added value of is that it makes
sente again, compared to if Black had not forced White to capture as in the previous diagram.
TAPJoshua?: Does
actually have added value? It seems to me that, at least in normal endgames,
is still sente even without
. White still has to defend where
is. So I think
should not even be played in the first place.
Bill:
is not sente without the stone on the marked point. In fact, White can continue as shown with sente. (Or White could even start with a play at 3.)
In a game vs. Yamashita Keigo in the 29th Meijin league, Cho Chikun plays kikashi with -
before strengthening his center group with
. (See commentary at
http://www.asahi.com/igo/meijin29/16/05.html.)
Despite the proverb about sacrificing kikashi stones, only is in any danger.
LukeNine45: Are these really kikashi? It looks to me like White is just taking all the free moves he can before playing
.
Bill: Yes. The commentary says, 右辺を白70から76と利かし . White plays kikashi on the right side with
-
.
My own comment is that these plays are more urgent because of White's running group. After White secures the group, they might not be so urgent.
LukeNine45: Interesting. I guess I'll have to think of kikashi as having a broader meaning. Thanks!
is a peep. Black can sacrifice
with b and d after White a.
From Charles Matthews - Shape Up! (p.48)
By the way, thank you for this excellent book. QWerner
Also, I think this is a 100 day thinking example for kyu players.
What is inside:
1. Kikashi ofcourse.
2. Shape, one way to use the Big Bulge and how to set it up.
3. Double purpose move. Not only in sense of the normal meaning of double purpose move. More in sense of the time changing purpose. First is needed to get
in the right place. Later it will treated lightly to get a strong position.
If W tenuki playing
elsewhere
is needed to cut. So this is another use of the Big Bulge here. Of course W tenuki is in this situation not the best idea, but this shows the dynamic of this shape. I will call it: A bunch of virtual live lines. In the moment where
is played all they exist, but only one get reality later (condensation). Therefore fixing a position reduce the value. From this point of view a good shape is a configuration which has enough nice future prospects to a brought variety of possible upcoming situations. A good feeling means than
to look somehow in the future knowing which live lines from different possible shapes over the goban will work later nicely together. This maybe is also called luck, I guess. QWerner
Questions
strongeye: So, could a ladder breaker be considered a kikashi if its in sente?
Answerer? : yes! it could!
Andy: The impression I get from reading English go literature is that the difference between "kikashi" and "sente" is that a kikashi stone is not immediately useful: it might become useful later or never depending on how subsequent play develops. In contrast, a sente play is one that has immediate value at the time it is played, that is, there is less of a speculative future value consideration of a sente play compared to a kikashi play. By this reasoning, in the examples on this page, the isolated peep at the tiger's mouth is kikashi, but the extension of white's wall threatening to kill is sente.
Bill: Good point, Andy! :) I think that what you say meshes with Sakata's explanation. Besides being sente, kikashi does work. The value of that work, as I see it, is not immediately apparent, but depends upon future developments. However, in the proverb about taking kikashi before living, the value of the kikashi is often immediate. Like most of language, things are not unambiguous. ;)
xela: It looks to me as though the "extension of white's wall threatening to kill" example is meant as a contrast with the previous example, to illustrate not-kikashi. The comment that shouldn't be sacrificed is what gives me that impression--therefore it's not kikashi irrespective of whether it's "really" sente?
See also
- Judging forcing plays
- Kikashi sente discussion
- Kikashi probe discussion
- Force as a mathematical term
[1] Sakata was known for playing kikashi early. On the contrary, Takagawa played kikashi late, and sometimes not at all. Games between these two are quite interesting in that regard.
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