Dual ladder breaker

    Keywords: Tesuji, Tactics, Problem

Chinese: 镇神头 (zhn shn tu)
Japanese: 鎮神頭 (chinshintou)
Korean: -

A dual ladder breaker or double ladder breaker is a move which breaks two ladders at a time.

Examples can be found in difficult TsumeGo-probles such as Igo-Hatsuyoron #6?, or actual, famous historic games (e.g., see the first recorded dual ladder breaker), not to be forgotten the variations from Joseki-variants (e.g., 2-4, two-high-kakari, outside-attachment...)

[Diagram]
Problem  

White to play. How to prevent two ladders?

[Diagram]
Ladder 1  

This is the first ladder.

[Diagram]
Ladder 2 (8 at 1)  

This is the second ladder. If W6 at B7, then B7 at a, and eventually White will still need to capture at W6.

[Diagram]
Solution  

The dual ladder breaker is W1.

[Diagram]
Discussion  

Technically it does break the 2 ladders, but now a and b are miai as they are both double atari. So this probably isn't a good example. ~srn347

Both a and b were double atari before, but the white+circle stones are not that important. Breaking the ladders keeps the black+circle stones dead, which gives White a big corner. Does c not break both ladders also? -JoelR


[Diagram]
Other attempts  

JoelR asked above: Does W1 not break both ladders also.

No, it does not. B can threaten one ladder and then capture some stones in a squeeze. There are probably other ways for black too.

[Diagram]
Other attempts - contd.  

See also:


Dual ladder breaker last edited by hnishy on May 24, 2018 - 07:01
RecentChanges · StartingPoints · About
Edit page ·Search · Related · Page info · Latest diff
[Welcome to Sensei's Library!]
RecentChanges
StartingPoints
About
RandomPage
Search position
Page history
Latest page diff
Partner sites:
Go Teaching Ladder
Goproblems.com
Login / Prefs
Tools
Sensei's Library