Ugly descent

    Keywords: Tesuji

Ugly descent or ugly sagari is a tesuji used in some particular types of capturing races in the corner. The name "ugly sagari" was coined by HolIgor.

[Diagram]

Ugly descent

In capturing races like this, the ugly-looking descent like W1 here might be the key to overcome problems with shortage of liberties. In this case, it is the only correct move.

[Diagram]

Ugly descent

If B2 hanes, then the clamp of W3 is the next move to remember.

[Diagram]

Ugly descent

B2 puts up a stronger resistance, but the same clamp at W3 still works. While B4 is a tesuji for gaining liberties, White is still ahead by one move because the ugly descent prevents Black from making the approach move at a.

[Diagram]

Mistake

If W1 plays on the 1-2 point instead, then B2 can throw-in. White can only respond by creating a ko with W3.

[Diagram]

Mistake (W7 at B2)

This is an elaboration on why W3 in the previous diagram has to start a ko. Because if W3 captures the B2 stone, then after the descent at B4, Black has the cut at B8 which prevents White's approach at a.

[Diagram]

Mistake

W1 here won't do either. After B2, White has no good response.

[Diagram]

Mistake

There is also a belly attachment tesuji at W1, but it only results in a ko, unlike the unconditional capture achieved by the correct ugly descent move.


See also


This is a copy of the living page "Ugly descent" at Sensei's Library.
(OC) 2016 the Authors, published under the OpenContent License V1.0.
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