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Yosumiru

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Enclosure
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3453Enclosure
MiddlegameJoseki
9x9TengenOpenings
TheUltimateProbe
3454Enclosure
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Probe
Path: EnclosureTechniques   · Prev: DefendingAnEnclosure   · Next: ProbePopularMisconceptions
Path: ForcingAndInitiative   · Prev: PushingBattle   · Next: ScreeningKikashi

  Difficulty: Advanced   Keywords: Strategy, Go term

A probe (Japanese: yosu-mi) is a play made in order to see how the opponent reacts. After a probe, the opponent must choose between one of two or three options. You should have planned your game so that none of these options are beneficial to your opponent. -- Morten Pahle

Also known as yosu-miru. See Yosumi vs Yosumiru. -- Eduardo Lopez H.

Mr. Yang Yilun, famous teaching pro, uses the term asking move. Probes usually ask the opponent to make a choice, say between inside territory or outside influence, which allows you to decide your strategy accordingly. --Bob McGuigan

Dieter Verhofstadt (1k) starts with a classic example of a probe given by Goran Siska and continues.

[Diagram]
Possible answers for Black

Possible local answers for Black range from a to d. I'm less sure about d, so I'll discuss the other three here in more detail.


[Diagram]
Block the probe from the outside

White crosscuts with W3 and plays kikashi with W5 and W7. Then White jumps out lightly with a, if this was a reducing manoeuver. Alternatively White leaves the situation for the moment and plays tenuki. Later in the game, the stones at W3, W5 and W7 will affect events at the top and in the center.



Charles B4 here isn't usually correct by pro standards, even though it appears in a number of books: see probe popular misconceptions.

[Diagram]
Reinforcing the outside

If Black thinks the outside is important, all outward aji will be removed by playing at B2. Naturally, this leaves the aji of White living in the corner with a. See the Tripod Group. With Black's territory reduced from the inside, White can now play a gentle reducing move, in case Black builds a moyo at the top.

Dave Sigaty: White may also push more aggressively at b. If Black answers at c, White plays a threatening to live with a better result than the tripod group. If Black answers instead at d, White plays c and escapes on the outside. This is discussed in The 1971 Honinbo Tournament, chapter 13.


[Diagram]
Blocking the probe from the inside

B2 chooses to protect the corner. Either White continues with a, probably reverting to answer 1, or plays tenuki. The aji of W1 enables White now to invade deeper than if Black had answered with B2 at a.

Dave Sigaty: Another continuation for White is the clamp at b. In Strategic Concepts of Go Nagahara gives the continuation Black c, White d, Black a, and White e. By removing the stones at W1, B2, c, and b, Nagahara shows by tewari analysis that Black has played at a in answer to White's probe at d - an unfavorable exchange (in the position shown in the book).

Charles Matthews In fact the common answer from the pros to White now at a is Black at b.


[Diagram]
Pulling back

Bob McGuigan: Pulling back with B2 is a common answer to W1 when Black wants to give White as little help settling her stone as possible. This leaves White with few forcing moves. If Black has a strong position in the middle of the upper side this can lead to a strong attack on W1. A standard response by White is a hane at a. Black will then usually pincer at b (if he doesn't already have a strong stone in that area) or play on top at c.


[Diagram]
The usual probe

This is the commonly-used probe in the small high enclosure.


[Diagram]
A continuation

This allows White to get two useful moves W3 and W5 and start to build on the outside; there is another common way to play with W3 at B4.



Yosumiru Example From Pro Game 1




Path: EnclosureTechniques   · Prev: DefendingAnEnclosure   · Next: ProbePopularMisconceptions
Path: ForcingAndInitiative   · Prev: PushingBattle   · Next: ScreeningKikashi

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