Kikashi

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  Difficulty: Intermediate   Keywords: Tactics, Strategy, Go term

A kikashi (利かし) is a sente move that produces a certain effect and can then be abandoned without any great loss. It is usually translated as forcing move.

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.


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

Otherwise forcing plays can be a mistake.


Examples

[Diagram]

Kikashi

B1 is a peep, a 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.

B1 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 B1 is a stone to be treated lightly. It is not an important stone. It is a kikashi.

[Diagram]

Sente

From the same diagram, we see that White can also peep at Black's marked tiger shape. This move is sente : it also forces the opponent to answer, but it has a local achievement too. W1 enhances the strength of the White wall, and should by no means be sacrificed, since that would imply the sacrifice of the whole wall !

[Diagram]

More kikashi

Suppose White is ahead in territory but Black has more influence. With W1 and W3, White forces Black to take some territory at the top. After his submissive answers, she jumps to W5. Her stones W1, W3 and W5, will have some influence on the proceedings in the center. If Black makes an attempt to capture W1 and W3, they should be sacrificed in order to strengthen W5.


What is the distinction between a kikashi and a probe?

Charles Something like the difference between a paratrooper and a spy?

Is this to say that a stone played as a probe is generally subsequently discarded whereas a kikashi may later be developed?

Charles Well, no. A probe tries to get information; so that you can make a better plan. A kikashi tries to 'force' the opponent to reply; the timing should be good, normally before the big battle starts.

Notochord My understanding: A kikashi is a move that is seen as having generally 1 response, which is (when the kikashi 'works') sente. A kikashi is a move that you can throw in whenever you want (within limits) to get an auxiliary exchange that (may) help directly with doing whatever you are trying to do. You usually expend some degree of aji that existed before the weakness or what have you was defended in exchange for something concrete that is helpful in a context-dependent manner, such as reducing white's liberties or getting a stone in a particular place. Its generally played against something weak, and works to help something 'nearby', in a tactical sense.

A probe, as charles said, looks for information, but maybe in a general sense than by the dictionary. It is a move generally played where your opponent is strong (in his area of influence, more accurately), and is a move that has many possible responses. It removes some of your aji, yes, but what it tries to do is force your opponent to make a specific decision, collapsing some of his own aji, and by making a direct decision, causing one of many of your (miai-ish) large scale strategic possibilities to be better than usually A schematic example of what a probe does: say you have strategic choice A (somewhat distant: a reducing move against some side) and choice B(a direct invasion along the side), which are both kindof mutually exclusive (invasion makes reduction pointless, and the response against the reduction secures the side). You have a probe play (some tsuki against a corner stone, for example) with two choices of response for your opponent: 1 (swallow the stone, let it live for a few points, and take big outside influence) and 2 (bar it from the corner, and try to kill it along the side). Say the exchange of your probe for 1 helps choice A (you get territory, your side invasion wasn't too good anyway, so your opponent protects what's already 'his' while you take corner points from him) and probe for 2 helps B (contributing to your side aji, or otherwise directly helping a potential invader). If you play A before the probe, you can't get the help of 1, since if you tried playing that probe after, he'd play 2. B similarly can't get the help of 2 when you get around to playing the probe. However, if you play the probe first, you can always pick A or B after to make it so that your opponent effectively made the wrong choice, thus improving the strength of your strategic action.

To summarize: Kikashi look for direct local gain from a definite (no choices) tactical exchange. Probes look for larger scale, global gain by an indefinite(your opponent has many choices of response) exchange, allowing you to make the plan that you would choose to each response synergize better with whatever choice (of many) you forced your opponent to make beforehand. It makes it so that your opponent's choice is made with less available information, and yours with more.

It seems I've gone on a bit, and sort of off the topic of this page. Feel free to edit this out or move it or clip it down to size in the near future.


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This is a copy of the living page "Kikashi" at Sensei's Library.
(OC) 2004 the Authors, published under the OpenContent License V1.0.
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