Black's turn! Can he trap the white stone? There are two ways for Black to play atari, but one is better than the other. Can you see which? This way, when White pulls out, he gets three liberties. This way, White only gets two liberties, so it's better for Black. What next? Which atari leaves White with the fewest liberties after he answers it? This way leaves White with three liberties again. And this way White only gets two. Can you work out how Black can keep this going? Still only two liberties! I think I'm getting the picture! This zigzag pattern is called a ladder. You can finish off like this ... ... or like this.

 Remember!

You can trap your opponent in a ladder if you can zigzag him all the way to the edge of the board.

Oh! By the way ...

If you find your stones caught in a ladder, don't keep adding more. Give them up while there still aren't too many!

"That's what I should have done."

 What do you think will happen here? The ladder doesn't work this time, because the triangled stone gets in the way. This stone is called a ladder block. In fact it's terrible. Next, White can play here, threatening two stones at once. This is called double atari. And if Black defends against that, White can still play double atari on the other side. Ouch! What about this one? Black's ladder block helps him, not White, so the ladder works.

 Remember!

A ladder block helps the side whose colour it is.

 Challenge!

In each problem, there are two ways to start a ladder. One works and the other doesn't. Click on the one you think works (A or B).

 Take a break!

You've earned it. When you're ready for more, click where you want to go.

 1 November 2003