BQM 108

  Difficulty: Advanced   Keywords: Tactics, Question

kokiri : I played a 3 stone handicap game against a British 2 Dan this weekend and the following sequence came up:


It was a three stone game and I invaded as marked. The continuation is below:


Low Invasion Of Mixed Three Space Extension describes white's response as aggressive and the continuation seems obvious enough...


B7 is a mistake as a for white is then pretty catastrophic, perhaps b is better but even then...


...after white plays a bit in the corner, I get to play at B8 and leave a dead shape (at the time, I read white at a as seki, but it appears to kill). there is some room for counterplay on both sides, but this still seems pretty poor for black.

unkx80: B8 at a lives.

This sort of invasion must be common, and one which, as a supposed 2kyu, I ought to know but from Get strong at Invading and other sources I can only find examples of the attachment shown in Low Invasion Of Mixed Three Space Extension.

Thus my question is: what went wrong?

Of course the black group on the left hand side also died later, but that is another story...

How is this?  

unkx80: How is this?

Right hand corner  

kokiri The Right hand corner was the following taisha (mis)variant, quite thick but I guess black has a workable position.

Charles Looking at pro games (not many examples), the lines used were B3 as suggested by unkx80, plus this idea:

Push out and cut  

Otake's idea  

This order of moves, actually my first thought, was played in an old game by Otake Hideo, leading to a ko.

Bill: I'm a square zero kind of guy. I would say, as a practical matter, what went wrong was the lack of preparation. In theory there may be nothing wrong with the invasion, witness professional play. But if you are taking 3 stones, why duke it out when you have a good alternative? IOW:

Prepare to invade  

B1 is a dual purpose move, securing the corner while preparing to invade at B3. The threat is often more potent than the execution, especially against a better executioner. ;-)

Tactical notes:

Obvious plays?  

After B1 - W2, B3 - W10 looks "obvious enough"? There is some unlearning to be done here. Black's play is heavy. B5 - W6 reduces the liberties of B1 and B3. B7 - W8 appears to strengthen White more than Black. Then B9 - W10 strengthens White without increasing Black's liberties. However, after B5 - W6, if Black plays at a instead of B9, White can reply with W9 and Black cannot respond at b.

BQM 108 last edited by Nico on September 23, 2003 - 12:28
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