| No Repetition (A rule called “Ko”)

No repetition ever.

Full disclosure - this is a rule that may confuse you at first. Fortunately, it is not as complicated as it appears at first glance. I for one think that a good ko fight is one of the most fun things you can have in Go, although many would disagree.

A game of Go can be really long. However, it must never be endless. To prevent the possibility of an endless game we have a rule called “Ko”.

Just imagine a situation like this one. Given enough stubbornness, players like these would be playing until they pass out. Feel free to watch for a while.

To prevent health problems connected with exhaustion, we have the following rule:

Can you ever capture that stone then? What are your options? Basically, you have two:

⬤ You deem the stone not important for now and play elsewhere, letting your opponent end the ko by connecting her endangered stone if she wants.

⬤ You deem the stone important enough to fight the ko. You still have to play elsewhere, but you try to find a move your opponent will feel compelled to answer to immediately instead of resolving the original ko; we call this a ko-threat. After that, you retake the ko stone and the fight is on!

Confusing? Check out the following examples. It will be clear in no time.

On the 19x19 board, there are usually much more than only one threat, so the ko fight can span several moves. The hard part, of course, is judging if a given threat is big enough that it needs to be responded to or whether it is more beneficial to end the ko. But hey, I said the rules are easy, not the game itself.