Life In 19x19

jlt wrote:Is it a tournament only for children, or a child-friendly tournament which is open to adults as well?

Clearly, it is a tournament only for friendly children. No grumps allowed!

Problem #43, White to play. Can White kill the group on the left?

My guess: the black group is alive. I thought I found a ko:

$$Wc White to play - ko?
$$ -------------------
$$ | . . . . . . . . X
$$ | . . . . . . O O O
$$ | . . . . . O O X X
$$ | . . . O . O . X .
$$ | . O O . . O X . O ...

I'll be there too!

Problem #42, what can White to?

$$Wc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . X X O B . . . |
$$ | . . O X X . X X X . X X O X O . O O . |
$$ | . . . O . X O . O O . . O . X X X X . |
$$ | . . . . . O . O ...

Elom0 wrote:Note the superko rule doesn't require keeping information of all previous board states, just the ones that follow capture.

I'm not saying you're wrong, but this does not seem obvious to me. How would you prove or verify it?

Maybe I am wrong but my count for the initial position is the following:
black : 38 stones + 2 points for territory = 40 points
white : 32 stones + 2 points for territory = 34 points
=>B+6
Do you agree?
No. That is the count if you assume all stones on the board are alive. But the upper left black ...

Gérard TAILLE wrote: Are you sure of your count when black and whites passes?

No. I wasn't sure yesterday when I posted, and I'm even less sure now that you asked.

Seems like it would depend on the exact rules used?

$$B Black to play
$$ --------------------
$$ |. X X O O X X O . |
$$ |O X O . O X X O X |
$$ |O X O O O X X O X |
$$ |. X O . O X X O . |
$$ |X X O O O X X O O |
$$ |O O O X X X X X X |
$$ |X X X X O O O O O |
$$ |X X X X O O X O . |
$$ |. X . X O . X X . |
$$ -------------------- Assume area ...

One nice thing about keeping formal track of my tsumego book results is that I now have a relatively objective way of measuring the difficulty of various collections. I tend to say things like "I think that book is somewhere between volumes 2 and 3 of Graded Go Problems for Beginners" but now I ...

Right, you unmark a stone by merging it with an unmarked stone of your color, and you need to remove an enemy group surrounding your marked stone in order to merge it with an unmarked stone of your color.

What if a string of one color subsequently gets surrounded by the other color? Do the ...

I got a japanese endgame book on 15x15 and I saw this position in the first problem. How many points is Black E17, in the deiri counting?

Thank you
I think it is one point.
If White plays first, White captures a stone and gets one point of territory, for a total White gain of two points.
If ...

Your move is exactly the one I played in my game so we both have the same wrong intuition, and/or we are both reluctant to cut and leave the cutting stones for later. Let's examine the continuation.

$$Bc ...

Position #81, Black to play, find the next 3-4 moves. Nothing complicated, but not on my radar.

$$Bc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . O ...

where did the formula 7+n(n+1) come from? (7 9 13 19 27 37 49 63 79 97 117)
https://littlegolem.net/jsp/forum/topic2.jsp?forum=20&topic=474 Interesting. It does seem to work fairly well.

I've always liked: nextSize = ceiling(currentSize*sqrt(2)) Conceptually, this means that the next board size ...

so a possible resolution to the problem, if black doesn't agree the kos are worth a point, the game is resumed and any stones still on the board after 4 passes are alive.
You mean "consecutive passes" right? You also have to decide what to do if neither side is willing to pass. And whether pass ...