Net versus ladder

    Keywords: Tactics

In general, capturing a stone in a net is considered better than capturing it in a ladder, because a net does not run the risk of a ladder block on the other side of the board.

There are exceptions to this rule, mostly when the extra liberty that a net gives is detrimental, in which case a ladder is quicker (the opponent is in atari until the end).

Table of contents Table of diagrams
White cuts
Net continuation
Ladder continuation
Taisha variation
Net continuation
Ladder continuation

Example

[Diagram]

White cuts

When white cuts at W1, black can capture this stone in a ladder or in a net.

[Diagram]

Net continuation

[problem- can't this net be defeated by the sequence c-d-e-f-g? sorry for poor notation.]

No, see here "White can't cut...". Black plays at g instead of f. White has no choice but to capture at f; B at h forces white to fill in at B2 and a couple more black moves capture the whole thing.

[Diagram]

Ladder continuation

The net is better, because the ladder variation allows white to play a ladder block somewhere along the path of the ladder

Tapir: Even if there is no ladder breaker played by White, Black needs to capture at a time just in case. That is what I took from Kageyama: to capture with a ladder you need two moves, to capture with a net only one.

Example of exception

[Diagram]

Taisha variation

In this variation of the taisha joseki. What the books say is that W7 is only playable when the ladder at a is good for White, capturing the stone B2 with the net White b and c isn't enough.

[Diagram]

Net continuation

[Diagram]

Ladder continuation

If the net continuation were good, White could play at W7 in the setup diagram independent of the ladder, thereby avoiding the most difficult variations.

After these plays, however, Black has a good result, and the possibility of a black peep at d remains. Also B4 forces W5. Both of these effects are there because the marked black stone is still on the board.

For comparison, see the usual result from the ladder variation. White's capture in the ladder forces B4.

(Note that the standard mistake here is White at a before W1: this loses sente and is an example of ignoring the 123 principle. However: checking with Lizzie shows that LZ prefers that mistake.)



See also


This is a copy of the living page "Net versus ladder" at Sensei's Library.
(OC) 2023 the Authors, published under the OpenContent License V1.0.
[Welcome to Sensei's Library!]
StartingPoints
ReferenceSection
About