Short extensions

    Keywords: Opening

The short extensions on the side are the high one-space extension, the one-space extension on the third line, and the knight's move extension from the third to the fourth line.

Of these, the one-space extension on the third line is the least common. Since the two-space extension will be preferred for its efficiency in most cases, the one-space extension, made when the room for a two-space extension is available, could be is a sign of some deeper theoretical or tactical reasoning.

One-space extension  

In fact this formation on the side can be considered rare in pro games.

Reinforcing the large low enclosure  

One place it does occur is in relation with the large low enclosure, which is insecure in the corner. When B1 is played as a checking extension against white+circle, Black is thinking hard about the aji in the left corner.

I started a thread a little while ago based on this sort of example:

Short extension approach  

The question being whether one could argue convincingly for Black tenuki next, or Black's diagonal attachment at a. It's more complex than that, if you look at real data.

A tactical example that impressed me.


Simple? Nothing is really simple when your opponent plays the 5-5 point. This is Matthew Macfadyen 6d - Zhang Shutai 7d from game 4 of the 1995 British Championship. The choice of W3 is presumably all to do with preserving the chance of White at a against Black at b. Don't think I'd have found this one.

Charles Matthews

JF How do we know who's Black and White? Is there an SL convention? FWIW I always put W first.

PS There is a Japanese name for the short extension on the side: Honinbo's ikken tobi.

Charles I always put Black first.

Short extensions last edited by CharlesMatthews on May 17, 2003 - 10:12
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