Cutting the Keima

Path: CuttingTechniques   · Prev: CutAcross   · Next: DrivingTesuji
  Difficulty: Beginner   Keywords: Shape, Tactics

Keima

[Diagram]

Reference diagram

This is a keima. It can be cut at a or b



Do not cut without support

[Diagram]

Cutting a keima

Cutting the keima without support will often rather strengthen the opponent.

After the cut with B1 and B3, White has extended from a crosscut and sente which is very advantageous for her. Next, W4 may capture the cutting stone in a ladder

So, cutting a keima is only advised when the attacker has support from other stones.



A genuine cut

[Diagram]

Cutting

When black+circle is present, the cut becomes more severe. If the ladder at a works for Black, B1 is a genuine cut.

Striking at the waist of the keima is usually the correct way to cut. We refer to that page to understand why that is so.

[Diagram]

Very severe

If on top of black+circle, there is also a black stone black+square, the same sequence results in a very severe cut.



Comparing to the one space jump

[Diagram]

No effective cut

If we compare the previous sequence with this one, where Black tries to cut a one space jump, we can see that White is reinforced and black+circle weakened, even if Black can next continue to cut at a. We can say Black has effectively cut himself here rather than White.

These diagrams show why, in hostile environment, the more stable one space jump is preferable for defending, whereas a keima is often more appropriate for attacking purposes in friendly environment.



Previous entries

below comments apply to a previous series of diagrams where the necessary presence of supporting stones for the cut was not sufficiently emphasized; they are kept here temporarily before this page goes into a WME mode

Bill: Isn't this lousy advice for a beginner? After all, the result of B1 - B3 is the same as White's extending to a crosscut.

fractic: I think the text above properly indicates that the cut has its risks and needs to be timed properly.

Bill: Well, I just did a Go Base search for this pattern:

[Diagram]

Very rare

including the empty points. There were exactly four hits. Out of hundreds of thousands, maybe over a million moves. You don't advise beginners, or anybody, to make such a play. If it is right, and they are good enough, they can find it. As for saying that a cut has risks, etc., that is asking beginners to exercise judgement they have not yet acquired. I say, get rid of this page entirely.

Yes, B1 may be often be a good play with supporting stones nearby. But not in itself. Show those supporting stones.

fractic: I agree that supporting stones do indeed make all the difference, but the diagram is just illustrating a general idea.

Out of curiosity, in your search how often did that keima appear without the black stones and no stones nearby?

Bill: I searched for the pattern without move numbers and got five hits. One was when White made the last play, not Black.

fractic: I ment to ask how often the white keima appeared by itself without B1.

Bill: Go Base doesn't just count, it retrieves references, and not all of them if there are many. It finds at least 100 such keimas, which is no surprise. :)

Dieter: The diagram is canonical and indeed needs to be immediately followed by an example of real play, justifying the presence of the keima AND the decision to cut.

Bill: It should also be explained that it is usually a bad idea. With all that rigamarole, why bother? I mean, if somebody wants to do a monograph on cutting the keima (or not), that would be nice, but it would not be a single page called Cut the Keima. Cutting the Keima, maybe, could be the parent page.

uffehellum: Cut first, think later, and smile while paying the price! Or, place a stone to break the ladder before rushing to cut the keima. We beginners absolutely should cut as early as possible. Notice that the cut is just as dangerous to white. Escaping with keima is like running with scissors. Both black and white should consider good placements of a supporting stone before the cut.


Further reading


Path: CuttingTechniques   · Prev: CutAcross   · Next: DrivingTesuji
This is a copy of the living page "Cutting the Keima" at Sensei's Library.
(OC) 2012 the Authors, published under the OpenContent License V1.0.
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