Red is three up but is going to lose that long chain, and it's got

eleven boxes in!

6 + + +-+-+-+      |r|r|r|5 +-+-+-+-+-+          |  4 +-+-+-+ + +        | | |3 + + + + + +        | | |2 + + + + + +        |   |1 + + + +-+-+  a b c d e f

I am *amazed* that red can win this one. If and when a second chain

forms in the bottom left, red will find he's lost the chain battle

and in particular is going to lose all 11 of those boxes in the 11-chain.

He has to struggle out of the position ensuring that, if blue keeps

control, he manages to land *one* measly box out of the nine in the

corner! On the other hand, my feeling for this one is that the best

play line is rather natural—I've certainly seen a part of it in

an actual game, and I actually fancy that I would have had *some*

chance of finding it over the board.

wcc

Aah, I see why we get those funny indentations now: it's spaces at the end of lines. Try again.

6 + + +-+-+-+      |r|r|r|5 +-+-+-+-+-+          |4 +-+-+-+ + +        | | |3 + + + + + +        | | |2 + + + + + +        |   |1 + + + +-+-+  a b c d e f

So just to keep this topic alive, do you now know how to play this one :

6 + +-+ + + +

\| \|

5 +-+-+-+-+-+

\|

4 +-+-+-+ + +

\| \| \|

3 + + + + + +

\| \| \|

2 + + + + + +

\| \|

1 + + + +-+-+

a b c d e f

and win ?

Hum same problem with spaces:

6 + +-+ + + +        |   |5 +-+-+-+-+-+          |4 +-+-+-+ + +        | | |3 + + + + + +        | | |2 + + + + + +        |   |1 + + + +-+-+  a b c d e f

I don't, but I have some tables that might tell me! The nim-value of the 3x3 icelandic corner is 0, and the nim-value of the chain is also 0 of course, so if I want to keep control I should sacrifice 2 in the top left. In fact, surely this wins. I will then win the long chain battle, which will give me *at least* 1 in the icelandic corner, and that and the top left hand corner which I get whilst losing the short chain battle, and the 11-chain, wins me the game.

wcc

[looks in tables] Right. I computed the value of 3x3 icelandic + 11-chain + 1-chain + 2-chain, and it's 3 to the player whose move it isn't, so the move I suggest does win (13-12), although I don't know if it's optimal.

wcc

Yes congrats you are right.

So after c5-c6 Red get two boxes and is faced with similar puzzle as yours : give you only 1 box in the icelandic corner by playing b3-b4.

Yes, so that brings us back to the original question: how does red (in the initial position) keep blue down to 1 box in the 3x3 corner? :-) The point is that blue must keep control: red already has 3 boxes so if blue loses control then red gets the 11-chain and wins. What surprised me was that he couldn't both keep control and get two boxes! If red plays it well, at least :-)