Dual ladder breaker
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...)
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 stones are not that important. Breaking the ladders keeps the stones dead, which gives White a big corner. Does c not break both ladders also? -JoelR
JoelR asked above: Does 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.
- Ladder breaker
- The first recorded dual ladder breaker
- Weird and Wonderful - Volume 1 - Extraordinary Moves by Professional Go Players: analyzes three examples of double ladder breakers from professional play.
- Cho Hye-Yeon's (8p) blog on dual-ladder-breakers