BQM31

Not joseki?  

White had played the double approach to the star point. Kogo's Joseki Dictionary^[1] says that Black should get out with the kosumi (on the other hand, actual practice says.../Modern Double Kakari).

However, he attached with . At I expected him to play at , because if White then cuts, Black sacrifices and and walks along the fourth line.

To my surprise he played kosumi-tsuke and, applying my basic instinct, I extended with . He then blocked the corner, leaving a very tempting cutting point.

(From the point of view of standard shape, should be played one point lower. Charles Matthews)

As so often, I muttered "must ... resist ... temptation" (c) Dilbert, but I fell for it and played the cut. Let me first show the alternative I had in mind.

Peaceful alternative  

reinforces the group and protects against the cut. Black must come back to protect against his cut, and then White plays on the other side. One cannot deny that the Black group has awkward shape; but on the other hand, considering White having played twice in a row and Black playing what seemed to be a bad move ( in first diagram), I felt this variation to be too soft.

WAR  

WAR, o-u-o-u-o-u-oh, what is it good for ? (Absolutely nothing).

Variation  

This was the alternative for in the previous diagram. Now White is faced with a soft option b and an aggressive one a, which again seems best.

The game  

Making ko in the corner was a very attractive prospect.

Continuation 1  

and were intended to be local ko-threats.

Continuation 2  

dissolved the ko with relatively good aji and Black's influence seems inferior (but not much) to White's 30-point corner.

Aji (4 at marked)  

Still, White will soon have to capture the cutting stones, otherwise Black either makes a small life in the corner, as in this diagram, or ...

Aji (4 at marked point)  

... turns the corner into an approach ko.

DaveSigaty: I think there is no ko here. Black cannot make an eye in the corner, and cannot squeeze White effectively enough on both the top and the right to prevent White from capturing the black stones in time.

Continuation 1 - variation  

DaveSigaty: I am wondering about White playing at here instead of using as a ko threat? After , looks like just the right spot (if Black a then White b and if Black b, White a follows).

Despite and it does not look like Black can attack the right side white stones very effectively, while the capture at c remains. If Black d, White e looks good enough and if Black e then White can cut across at d.

If Black plays on the left after then I think he will find it difficult to find an effective ko threat when White uses to retake the ko.

The simple way  

White is afraid of the cut with because now he doesn't have a liberty anymore at . But still Black cannot cut with . All White has to do is play hane with and connect. Now if Black defends the corner White captures with a. Or, if Black defends , White plays b.

This is the same as Holigor's first diagram. He added a few more moves and I have to say White is definitely better in that diagram. Her territory is better than the black influence. And further, she has sente. Even if the ladder works for Black, White can always play a ladder breaker.

Still the simple way  

The only problem seems to be . But now White plays atari at and still has a and b.

The idea in this position is that the black corner is too weak to attack White. And that White should not play atari on the stone until she knows which atari to play.

Lucretiu Calota 5 dan from Romania

Simpler still?  

Is this not simpler, or have I missed a killer response for Black?

Black is thick  

Charles Doubtless will follow. Black then has a thick shape.

You could argue that White now at a is a trade of territory for influence.

A better trade  

Trouble is, wasn't the best way. Here we assume / exchanged.

Now White could take sente. If White wants perfect shape round here, White at b is good. Certainly a stone at b does much more work than at c.

Going right back to the start:

Correct style to cut?  

This is a way for White to start an immediate fight in the centre. Since White's connection at a brings the corner close to a carpenter's square shape, this seems OK for White.

In fact this isn't bad, developing on both sides.

Rich Thanks, Charles; that final pattern looks nice. I was thinking of exchanging territory for influence; the reason I decided against the 3-3 point you showed in 'a better trade', was because the push at c seems to give the cut or the corner to black. Given the aim of the choice was territory, the corner should then be kept, surely?

A worrying cut at a  

Anyhow, at this point it gets complicated, which was what I was trying to avoid... :) It's my mid-kyu timidity, you see...

Black's cut  

Charles I don't know about 'complicated'. Giving up stones like here is actually a way to simplify things.

Consider that White has already taken sente once here. I'm assuming of the previous diagram played at the 2-2 point instead. Black can play atari if he wants and get an answer.

After White takes sente again. There are the two marked points on the right side, for later. And certainly might get out soon.

The main point is that Black has played one more stone here than White, now (i.e., looking at the local tally, you expect Black to be doing better).