Improve Fast In Go

© Milton N. Bradley 2008

Chapter 4 - Peeps and Cuts

Peeps and cuts are among the most common mechanisms by which weak stones arise.

The primary differences between a peep and a cut are:

   - A peep’s value is often almost fully realized at the moment it succeeds in forcing the opponent’s connection
, so that in many cases it may then profitably be (at least temporarily) “abandoned”, to thereafter serve primarily as Aji.

   - Most cuts result in the formation of a new (often weak) group, which thereafter must be watched and defended.

Although there is no single simplistic “rule of thumb” that can provide unerring guidance in deciding whether it’s best to cut or peep in any given position, in general, and considering only the local situation:




The problem confronting the double digit Kyu player is that (s)he’s typically uncertain of whether or not any given cut should succeed ! And considering that their own play is probably going to be less than perfect, in games in which the main objective is learning and improvement rather than just victory, the best strategy is to cut, and then learn from experience both how to correctly appraise that decision in advance and how to conduct the resulting fight once you’re embroiled in it.



Dia 1 In this variation of a popular 3-4 point Joseki, Black plays for thickness while conceding the corner territory to White.

Dia 2 After the atari of B10, W11 connects, and then B12 makes a double “Tiger’s Mouth” virtual connection.

Dia 3 Next, the peep of W13 is a Kikashi which is answered by the connection of B14, and this is followed by the similar W15 peep, B16 connection exchange.

After this, the White corner has the miai of “a” and “b” for its life so it’s safe! And, in the absence of other nearby friendly stones to help, there is no reasonable attack that White can currently expect to successfully mount against Black’s solid enclosing wall.

So local action often ends for the moment, leaving this situation as is until later events make it clear what each side needs to do next locally.

IMPORTANT! Just because a peep has been played (and answered), it distinctly does not imply that direct use must be made of that peep stone either immediately or ever! That may in fact occur, but at least as often a peep stone will be used indirectly to attain some other desirable goal (most often as a ladder breaker), or may even simply be temporarily “abandoned”as Aji, for possible later use.

With that in mind, let’s now look again at the situation of Dia 3 and appraise the implications generated by the two peeps of W13 and 15 and their forced responses.

The first thing that we notice is that W13 is a completely isolated lone stone pressed against a solid Black position, and W15 is only a bit stronger because of its assist from W3. So both of these peep stones are, by definition, more or less weak!

In response to these peeps, we see that Black has not only been forced to add two stones of his own, but also has been forced into a position which, although thick, not only has absolutely no shape, but is also already partially enclosed and inhibited from expanding readily.

The overall assessment of the position in Dia 3 is therefore:

   - On balance, Black is clearly the stronger on the outside.

   - If White correctly views W13 and 15 as expendable potential sacrifices rather than as essential assets which must be maintained even at cost, for the moment White stands at least equal overall because of their presence.

Whether this Joseki integrates better into the global strategy of one side or the other depends on the position on the remainder of the board and is an issue beyond our present focus, so it will not be discussed here.


Figure 1 In this early middle game between two 4D players, the key issue at the moment is the fight in the upper right that has just begun between the enclosed and still unsettled B47-55 group and the enclosing W10-54 stones, which are still lacking shape and which therefore must be strengthened before he can safely attack Black.

The solution to this dilemma that White conjured up was W56, peeping into the cutting point at “a” in Black’s lower right group. Because the B1- 43 stones would be forced into a dangerous (and quite possibly disastrous) fight if cut off, that gave Black essentially no choice but to connect at “a”.

Having thus helped stabilize his own weak stones in Sente, White was then able to turn his attention back to the desired attack on the weak Black group in the upper right corner. So in this position the peep was the perfect move!


The Typical Intention Of A Cut

Is To Permanently Separate

A Group Of Opposing Stones


and that almost invariably means that the cutting stone(s) will subsequently have to be reinforced/supported as required.

A cut therefore typically initiates an important long term commitment.


Diagram 4 In this position from a game between a 9D and a 7D, the hane of B1 is a typical continuation of the Joseki in the corner.

After the exchange of W2, B3, the necessary continuation thru B7 resulted in the creation of a weak Black group, in return for which White’s thickness has been effectively neutralized.

Whether or not this turns out to have been good strategy by Black will depend on the followup by both sides.

Cuts Are Also Commonly Used
To Make Shape Or To Facilitate Escape



Diagram 5 The cut of B8 followed by the forced sequence thru B12 sets up the capture of the marked White stone, resulting in White’s superb thickness in return for Black’s securing a large corner.

Now let’s look at a position in a game between two 5 D’s in which making a judicious cut was the best way for a nearly trapped group to escape.



Diagram 7 Cutting with W1 is the way to begin.! That makes W3, 5, 7, 9 and 11 all forcing moves, sacrificing 2 stones (W1 and 5), and then moving smoothly out with W13., and leaving behind the potential for an almost certain eye at the top. Beginning instead with either W3 or W7 would allow either the connection of B1 or the extension of B10, and then White will have to flee eyeless!

The outcome of a cut will frequently not only be decisive (as in these examples), but sometimes unpredictable, at least among players at less than a very high level, with the result that:

Making A Judicious Cut

Is Often The Most Powerful Way To Play,

And Sometimes

The Only Possible Route To Victory



Cutting Can Be

Fraught With Danger



Diagram 8 This is a not uncommon position, especially in high handicap games.

At first glance, it appears that a White cut at “a” will be big, so that it’s necessary for Black to protect against it. But that’s only an illusion!

On deeper analysis, it becomes apparent that a White cut at “a”is actually infeasible!


Dia 9 If W1 cuts, expecting (or hoping for) this submissive B4 in response to W3, he may be in for a big surprise because ...

Dia 10 After this B4 instead, if White foolishly continues as shown here, Black has this forcing sequence (a “squeeze”) with which to ruin White’s shape. Then ...


Diagram 11 After the atari of B10 forces the connection of W11 (with simply awful shape), the exchange of W13 for B14 is necessary to allow W15 to be an atari, which then forces B16 and gives White time for W17 to move out.

This diagram shows one continuation after the plausible diagonal move of W17. Unfortunately for White, it fails. But there are lots of chances for Black to go wrong in the resulting fight, so White may well live instead if Black plays weakly.

White’s problem is that even if he escapes after W15, the outside strength that Black will build up while attacking his ever growing weak group should doom his overall game prospects! On the other hand, if Black isn’t a particularly strong fighter, or if this sequence is used by White as ko Aji, it might still be very dangerous for Black.

So on balance, unless White is a particularly strong fighter or believes that Black is an especially weak one, W1 at “b” in Dia 9 instead of the cut is objectively the better way for White to play. The problem is that in most global situations that move won’t be Sente, so it must be timed correctly!

Cuts And Ladders

Cuts frequently give rise to a ladder. In those cases, wherever feasible the “rule” is

Capture Any Cutting Stone(s)

As Soon As Possible



Diagram 12 When B1 ataris the marked White cutting stone, it sets up a ladder which favors Black because it runs into the Black stones in the lower right corner.

Then W2 is a ladder breaker! But instead of playing the natural appearing B“a”, which would reinstate the ladder, Black’s best response is to immediately capture the White stone with B3, removing its dangerous Aji, perfecting his thickness, and thereby strengthening his now nearly complete moyo on the upper side.

That this allows the excellent W4 is regrettable, but unavoidable.

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