Ladders and a Joke

A ladder is a basic form that happens often on the GO board. In its most basic form, it happens when one group of 5 stones puts a pair of connected stones in atari. It is something you need to know about so you can avoid getting caught in one. It is fundamental enough that the proverb is "If you don't know ladders, don't play GO".


Here we have a bunch of stones that could become a ladder. If black gets one more stone on C17 or D17 he will put white in atari.


Here we see the ladder. Black puts white in atari with C17, white extends to get 2 liberties, black takes one and it is atari again. Repeat until you reach the wall. Notice the zig-zag, stair step pattern made by the white stones - this is the signature of a ladder. By choosing to start the ladder with C17, black pushed white up and to the right. If he had chosen D17 instead, he could push up and to the left.


As the ladder approaches a side, black has to break the pattern a little to avoid an atari of a stone against the side, but as you can see above, one more black stone will kill the entire white group! (White at D19 leaves C19 for black as the capturing move.)


Ladders are deadly, but sometimes they don't work. All white needs is one extra stone to help escape the deadly ladder. Stones that do this are called "ladder breakers". Set this up on a board and see why both A16 and F18 are ladder breakers. One breaks the ladder started with C17 and the other breaks the D17 ladder. As the ladder pattern forms those breakers give white an atari on a single stone in the ladder that helps escape the atari on the large ladder group.


Potential ladders are formed on the board all the time - can you find any in the diagram above? The player who gets to go next can start a ladder on their opponent.

So, now you know about ladders! A few more thoughts to deal with them in game. If you see you are caught in a ladder, look to see if you have any ladder breaker stones to help you escape. If you don't, stop trying to save the group and play elsewhere. If your opponent doesn't kill the group instantly, try to play a ladder breaker sometime later. If your opponent misreads the purpose of that stone and doesn't kill the group in the ladder, you can now return to playing and breaking out of it. Secondly, if you are in a game where you have a ladder or are caught in a ladder that you can break, play it out to the end! Get as much advantage as you can with the ladder - drive it as far as you can before capturing or breaking it. This should only happen if your opponent doesn't know about ladders (although there are known games by professionals where they misread ladders).

Well, that was a long post just to set up the following joke (which I found on another blog somewhere):

Q: How many 30-kyus does it take to change a light bulb?
A: They can't do it, because they don't see the ladder.