Life In 19x19

It seems that the send two rerurn one corner failed to distinguish PSK and SSK.

Gérard TAILLE wrote:
Unless somebody tells me she wish continue to search the original martian problem without knowing a solution, I will give you one of my solutions (on a 11x11 goban) next week, i.e. one month after my first post.

Good search!

Now, one moth has passed.

As promised, after one month I give you a solution of this martian problem

Black to play

Click Here To Show Diagram Code

[go]$$B
$$ -----------------------
$$ | . a O O . O O . O . |
$$ | X X O X O O X O O O |
$$ | . O O X X X X X X X |
$$ | O O X X . X . X O O |
$$ | X X X X X X X X O O |
$$ | O O O O O O O X X b |
$$ | d X d O O O O X O O |
$$ | O O O O O X O X O . |
$$ | c O X X X X O X O O |
$$ | O X . X . X O X O . |
$$ -----------------------[/go]

Black plays "a" with japanese rule, "b" or "d" with PSK rule and "c" with SSK rule.

Though it was very difficult for me to find such position, when seeing the result, it looks surprisingly rather simple.

In SSK rules the idea is to save black stones in the bottom by the well known send three return two in the bottom left corner.

For distinguishing PSK and japonese rules the idea is simply to use the japonese particularity of counting seki. The point is the following:
with territory counting, a move at "a" gains 4.5 points which is greater than 4 points for a move at "b".
In the other hand, with area counting, a move at "b" gains 5 points which is greater than 4.5 points for a move at "a".

It remains to look at a move at "d" when using japonese or PSK rule. The correct answer to a move at "d" being a white move at "a", you can easily see that a move at "d" is correct under PSK rule but not under japonese rule.

I hope you will appreciate this position!

If your are interested I found a more difficult position using the bent four in the corner

Taking my last proposal on a 10x10, eventually I managed to draw the position in a 9x9 board.
I am happy to show you the following new martian position on this small board, hoping I am nor wrong:

Click Here To Show Diagram Code

[go]$$B
$$ -----------------------
$$ | . j O O O . O . O |
$$ | X . O X O O X O . |
$$ | O O O X X X X O O |
$$ | X X X X X X . X c |
$$ | O O O O X . X X O |
$$ | c X c O X X X X O |
$$ | O O O O O O O X O |
$$ | a O X X X X O X X |
$$ | O X . X . X O X . |
$$ -----------------------[/go]

A japanese player (I mean no points in seki) must play at "j".
An AGA player (I mean SSK use) must play at "a"
A chinese player (I mean PSK use) must play at one of the three points "c"