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...

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 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: 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...

unkx80: How is this?

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 as suggested by unkx80, plus this 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:

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

Tactical notes:

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

Path: <= Big Question Mark =>

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

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