AshleyF/StoneCountingRules

One breathing space left  

The stone has only one breathing space left (at ). Notice that only the adjacent empty points following the lines count (not the diagonal ones).

Capture!  

If Black () takes this last "breath" then the white stone is removed.

Run!  

If White "runs" with , then now the two white stones form a "group" that has three breathing spaces (marked ).

Group capture!  

It is still possible for Black to capture the whole group.

Suicide?  

Black can also capture in this position (at ). It looks like suicide (the stone would have no breathing space for a moment) but he can "hold his breath" while he captures and gets a breathing space back.

Black captures... and they keep doing this back and forth forever?  

That's why there is the rule that you cannot repeat the position.

Edges allowed  

Even the very edges and corners of the board are allowed...

Building "walls"  

You begin to "wall off" areas of the board, but you're free to play "inside" your opponent's area (like ) if you like.

Fighting  

There is a kind of "fighting" that takes place as players defend their areas.

Capture!  

Here we have our first capture. takes the last breating space of and it's removed from the board.

Holding breath  

After a couple more plays we have an interesting position: White can "hold her breath" for a monent and play at to capture the stone.

Ko!  

Notice that after the play, gets a breathing space at from capturing so it's not suicide. This is another interesting position: Black cannot just capture back at now. That would make the board exactly as it was before; repeating the position. This is a "Ko". If it were allowed, Black and White could go back and forth like this forever and the game would never end. Instead, Black has to play somewhere else now.

What can Black do?  

As we just said, Black cannot play at . Also, the top two points would be simple suicide for Black. Finally, if he played either of the bottom two points, then White would next be able hold her breath again and capture the whole black group at the bottom! In this situation, Black would rather not play at all. He passes.

Now Ko is allowed  

White gets to go again; capturing the two stones. Now the board has changed and Black can recapture the Ko with without repeating the position.

White cannot recapture  

White cannot recapture the Ko immediately because that would repeat the position. So she plays elsewhere () and Black fills the Ko with .

Note: We're using StoneCounting, so is not silly.

Game over  

Now neither player wants to put a stone down. Can you see that all the remaining empty points are either immediate suicide or would allow their opponent to capture all their stones in the next play? Here both players pass and the game is over.

Notice how both sides have two separate empty points left. These are called "eyes" and this is one of the keys to the game. A group with two eyes can never be captured. They are called "alive".

Let's count the stones on the board: 11 for White. 10 for Black. That means White wins by one point - Good game!

Game over  

White wins by one point in this ending position as well. But look closely, none of the groups have two eyes (the white group even has no eyes at all!). Neither player wants to put any more stones down in this position because it would leave them with only one breathing space and they'd be captured in the next play. As long as both players refuse to play and instead pass here then everything stays on the board and is counted. This situation is called a Seki.