Life In 19x19

Posted: **Tue Jul 20, 2021 12:23 pm**

I am as puzzled as Gérard is about all of this.

So Gérard posted this diagram:

Click Here To Show Diagram Code: [go]$$Bm10 $$ -------------------------- $$ . . . . . X O O X . . . | $$ . . . 3 X 2 X O . X O O | $$ . . . . . X O O O O 1 O | $$ . . . . . . X X X X O X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

I've copied the resulting shape below. It is clear to me that white needs to win the ko at 'a' in order to live. There is no double ko here. Whether black has local threats or not shouldn't matter, should it?

Click Here To Show Diagram Code: [go]$$ White to move $$ -------------------------- $$ . . . . . X O O X . . . | $$ . . . X X O . O . X O O | $$ . . . . . X O O O O X O | $$ . . . . . . X X X X a X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

The only difference I see between this tsumego and other tsumego that are commonly accepted to end in "life / death by ko" is that the ko at 'a' is already present at the beginning of the tsumego.

Posted: **Tue Jul 20, 2021 12:51 pm**

Farodin wrote: I've copied the resulting shape below. It is clear to me that white needs to win the ko at 'a' in order to live. There is no double ko here. Whether black has local threats or not shouldn't matter, should it?

$$ White to move
$$ --------------------------
$$ . . . . . X O O X . . . |
$$ . . . X X O . O . X O O |
$$ . . . . . X O O O O X O |
$$ . . . . . . X X X X a X |
$$ . . . . . . . . . . X . |
$$ . . . . . . . . . . . . |
$$ . . . . . . . . . . . . |
$$
Click Here To Show Diagram Code
[go]$$ White to move $$ -------------------------- $$ . . . . . X O O X . . . | $$ . . . X X O . O . X O O | $$ . . . . . X O O O O X O | $$ . . . . . . X X X X a X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

That position is possible because

played a ko threat elsewhere, and

responded. Whether you accept

-

is a matter of convention.

Posted: **Tue Jul 20, 2021 1:47 pm**

White is alive in double ko. I really don't understand the objection to this.

Posted: **Tue Jul 20, 2021 1:55 pm**

Kirby wrote:White is alive in double ko. I really don't understand the objection to this.

Click Here To Show Diagram Code: [go]$$ White to move $$ -------------------------- $$ . . . . c X O O X . b . | $$ . . . X X O . O . X O O | $$ . . . . . X O O O O X O | $$ . . . . . . X X X X a X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

Consider at the beginning that black is only interested by winning the ko at "a". It is white to play but for black b and c are miai, that is the point.

Posted: **Tue Jul 20, 2021 3:48 pm**

I get your point - black insists on the ko at 'a'.

Then, I agree with you. I think it's ko.

Posted: **Tue Jul 20, 2021 4:57 pm**

Click Here To Show Diagram Code: [go]$$Wc White to move $$ -------------------------- $$ . . . 6 1 8 O O X . 2 . | $$ . . 5 X X O . O . X O O | $$ . . . 7 3 X O O O O X O | $$ . . . . . 4 X X X X 9 X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

Posted: **Tue Jul 20, 2021 10:37 pm**

Shaddy wrote:
$$Wc White to move
$$ --------------------------
$$ . . . 6 1 8 O O X . 2 . |
$$ . . 5 X X O . O . X O O |
$$ . . . 7 3 X O O O O X O |
$$ . . . . . 4 X X X X 9 X |
$$ . . . . . . . . . . X . |
$$ . . . . . . . . . . . . |
$$ . . . . . . . . . . . . |
$$
Click Here To Show Diagram Code
[go]$$Wc White to move $$ -------------------------- $$ . . . 6 1 8 O O X . 2 . | $$ . . 5 X X O . O . X O O | $$ . . . 7 3 X O O O O X O | $$ . . . . . 4 X X X X 9 X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

Thank you, I didn't see the nose attach at 5. So now I can agree that it is alive in double ko

Posted: **Wed Jul 21, 2021 1:06 am**

Shaddy wrote:
$$Wc White to move
$$ --------------------------
$$ . . . 6 1 8 O O X . 2 . |
$$ . . 5 X X O . O . X O O |
$$ . . . 7 3 X O O O O X O |
$$ . . . . . 4 X X X X 9 X |
$$ . . . . . . . . . . X . |
$$ . . . . . . . . . . . . |
$$ . . . . . . . . . . . . |
$$
Click Here To Show Diagram Code
[go]$$Wc White to move $$ -------------------------- $$ . . . 6 1 8 O O X . 2 . | $$ . . 5 X X O . O . X O O | $$ . . . 7 3 X O O O O X O | $$ . . . . . 4 X X X X 9 X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

Fine Shaddy, as Farodin, I didn't see the nose attach at 5.

Click Here To Show Diagram Code: [go]$$Bm10 $$ -------------------------- $$ . . . . 4 X O O X . . . | $$ . . . 3 X 2 X O . X O O | $$ . . . . . X O O O O 1 O | $$ . . . . . . X X X X O X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

That prove that my move

was not correct, allowing you to take at

in good conditions.
Far better seems:

Click Here To Show Diagram Code: [go]$$Bm10 $$ -------------------------- $$ . . . . . X O O X . . . | $$ . . . . X 2 X O . X O O | $$ . . . . 3 X O O O O 1 O | $$ . . . . . . X X X X O X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

Click Here To Show Diagram Code: [go]$$Bm10 $$ -------------------------- $$ . . . . 4 X O W X . 5 . | $$ . . . . X O . O . B O O | $$ . . . . 3 X O O O O X O | $$ . . . . . . X X X X . X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

Now I do not think you will play the sequence

which looks quite bad due to the awful previous exchange of the two marked stones.
If the idea is to escape on the left then I think white should play

Click Here To Show Diagram Code: [go]$$W $$ -------------------------- $$ . . . . . 4 3 . 2 . . . | $$ . . . . X 5 X 1 . . O O | $$ . . . . . X O O O O X O | $$ . . . . . . X X X X . X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

with a good result for white

Due to this variant I think black

may be a mistake and I prefer simply taking the corner with ko by:

Click Here To Show Diagram Code: [go]$$W $$ -------------------------- $$ . . . . . . 3 . 2 . . . | $$ . . . . X . X 1 . 4 O O | $$ . . . . . X O O O O X O | $$ . . . . . . X X X X . X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

In any case thank you for your help Shaddy, I appreciate.

Posted: **Wed Jul 21, 2021 1:32 am**

Click Here To Show Diagram Code: [go]$$Bm10 $$ -------------------------- $$ . . . . . X O O X . . . | $$ . . . a X 2 X O . X O O | $$ . . . b 3 X O O O O 1 O | $$ . . . . . . X X X X O X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

It is irrelevant, whether

is at a or at b alternatively.

Click Here To Show Diagram Code: [go]$$Bm10 $$ -------------------------- $$ . . . . . X O O X . . . | $$ . . . . X O . O . X O O | $$ . . . . X X O O O O X O | $$ . . . . . . X X X X 4 X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

Click Here To Show Diagram Code: [go]$$Bm10 $$ -------------------------- $$ . . . . . X O O X . . . | $$ . . . . X O . O . X O O | $$ . . . . X X O O O O . O | $$ . . . . . . X X X X O X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

ko threat

elsewhere

Click Here To Show Diagram Code: [go]$$Bm10 $$ -------------------------- $$ . . . . . X O O X . . . | $$ . . . . X O . O . X O O | $$ . . . . X X O O O O 7 O | $$ . . . . . . X X X X O X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

Click Here To Show Diagram Code: [go]$$Bm16 $$ -------------------------- $$ . . . . . X O O X . 2 . | $$ . . . . X O 3 O . X O O | $$ . . . . X X O O O O X O | $$ . . . . . . X X X X 4 X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

White lives in double-ko.

Posted: **Wed Jul 21, 2021 1:49 am**

Cassandra wrote:
$$Bm10
$$ --------------------------
$$ . . . . . X O O X . . . |
$$ . . . a X 2 X O . X O O |
$$ . . . b 3 X O O O O 1 O |
$$ . . . . . . X X X X O X |
$$ . . . . . . . . . . X . |
$$ . . . . . . . . . . . . |
$$ . . . . . . . . . . . . |
$$
Click Here To Show Diagram Code
[go]$$Bm10 $$ -------------------------- $$ . . . . . X O O X . . . | $$ . . . a X 2 X O . X O O | $$ . . . b 3 X O O O O 1 O | $$ . . . . . . X X X X O X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]
It is irrelevant, whether is at a or at b alternatively.

$$Bm10
$$ --------------------------
$$ . . . . . X O O X . . . |
$$ . . . . X O . O . X O O |
$$ . . . . X X O O O O X O |
$$ . . . . . . X X X X 4 X |
$$ . . . . . . . . . . X . |
$$ . . . . . . . . . . . . |
$$ . . . . . . . . . . . . |
$$
Click Here To Show Diagram Code
[go]$$Bm10 $$ -------------------------- $$ . . . . . X O O X . . . | $$ . . . . X O . O . X O O | $$ . . . . X X O O O O X O | $$ . . . . . . X X X X 4 X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

$$Bm10
$$ --------------------------
$$ . . . . . X O O X . . . |
$$ . . . . X O . O . X O O |
$$ . . . . X X O O O O . O |
$$ . . . . . . X X X X O X |
$$ . . . . . . . . . . X . |
$$ . . . . . . . . . . . . |
$$ . . . . . . . . . . . . |
$$
Click Here To Show Diagram Code
[go]$$Bm10 $$ -------------------------- $$ . . . . . X O O X . . . | $$ . . . . X O . O . X O O | $$ . . . . X X O O O O . O | $$ . . . . . . X X X X O X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]
ko threat
elsewhere

$$Bm10
$$ --------------------------
$$ . . . . . X O O X . . . |
$$ . . . . X O . O . X O O |
$$ . . . . X X O O O O 7 O |
$$ . . . . . . X X X X O X |
$$ . . . . . . . . . . X . |
$$ . . . . . . . . . . . . |
$$ . . . . . . . . . . . . |
$$
Click Here To Show Diagram Code
[go]$$Bm10 $$ -------------------------- $$ . . . . . X O O X . . . | $$ . . . . X O . O . X O O | $$ . . . . X X O O O O 7 O | $$ . . . . . . X X X X O X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

$$Bm16
$$ --------------------------
$$ . . . . . X O O X . 2 . |
$$ . . . . X O 3 O . X O O |
$$ . . . . X X O O O O X O |
$$ . . . . . . X X X X 4 X |
$$ . . . . . . . . . . X . |
$$ . . . . . . . . . . . . |
$$ . . . . . . . . . . . . |
$$
Click Here To Show Diagram Code
[go]$$Bm16 $$ -------------------------- $$ . . . . . X O O X . 2 . | $$ . . . . X O 3 O . X O O | $$ . . . . X X O O O O X O | $$ . . . . . . X X X X 4 X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]
White lives in double-ko.

My proposal was to play

Click Here To Show Diagram Code: [go]$$Bm16 $$ -------------------------- $$ . . . . 3 X O O X . 2 . | $$ . . . . X O . O . X O O | $$ . . . . X X O O O O X O | $$ . . . . . . X X X X . X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

to continue fighting the ko on the right till a black connection.

Posted: **Wed Jul 21, 2021 4:31 am**

Gérard TAILLE wrote:
Shaddy wrote:
Due to this variant I think black may be a mistake and I prefer simply taking the corner with ko by:
$$W
$$ --------------------------
$$ . . . . . . 3 . 2 . . . |
$$ . . . . X . X 1 . 4 O O |
$$ . . . . . X O O O O X O |
$$ . . . . . . X X X X . X |
$$ . . . . . . . . . . X . |
$$ . . . . . . . . . . . . |
$$ . . . . . . . . . . . . |
$$
Click Here To Show Diagram Code
[go]$$W $$ -------------------------- $$ . . . . . . 3 . 2 . . . | $$ . . . . X . X 1 . 4 O O | $$ . . . . . X O O O O X O | $$ . . . . . . X X X X . X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]
In any case thank you for your help Shaddy, I appreciate.

Wow, this position is more interesting than I thought. If black plays like that, can white just do this?

Click Here To Show Diagram Code: [go]$$W $$ -------------------------- $$ . . . . . . 3 . 2 b a . | $$ . . . . X 5 C 1 7 4 O O | $$ . . . . 6 X O O O O X O | $$ . . . . . . X X X X c X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

Then if black plays at 'a', there's another double ko at 'b' and 'c'.

Posted: **Wed Jul 21, 2021 11:24 am**

Fancy that! A discussion on L19. Maybe I should buy a lottery ticket this week....

Just a small corrective: in the original this is problem 65, not 76, it is not marked as a 'to live' (or ko) problem, nowhere is it described as 'unconditional' life (it says "lives with double ko"), and the categories given in SL do not exist.

Furthermore, the title and the introductory text, as well as conventions, guide us to the double ko solution. In particular, the introduction tells us that the collection is a mixture of old and new problems. The main characteristic of old problems is that they show us the myoki (wonderful wizardry) in the solutions. The problems were objets d'art, intended for discussion (exactly as we have here). The "solution" was to find the beauty, the wizardry, the talking point. A mini-algorithm approach might give an easier (and uglier) solution, but that is to miss the point.

Although this enlightened and enlightening way of viewing problems was essentially a Chinese one, and was underpinned by names for problems that either led to spotting a fancy solution or that gave food for thought in the discussion, the Japanese encapsulated the implied conventions in the term tsumego. A tsumego is a compressed or miniaturised go position. The rest of the board (or the state of play) doesn't matter. That convention also applies to "new" problems. A problem is a problem, not a mini-game. The derived conventions (such as ladders work, ko threats elsewhere are irrelevant) are well known but are sometimes still spelled out in books and magazines. This is not least because tsumego problems have often been used as prize competitions and so competition rules have to be clearly stated. Shikatsu Myoki was the result of precisely such a prize competition series in a newspaper.

So, while finding new wrinkles, as here, is commendable, it does not mean that the original problem was in any way wrong or flawed (although, of course, some old problems have been found to be flawed, most often because of missing or misplaced stones, probably due to editorial interventions, or carvos).

Posted: **Wed Jul 21, 2021 2:30 pm**

Kirby wrote:
Gérard TAILLE wrote:
Shaddy wrote:
Due to this variant I think black may be a mistake and I prefer simply taking the corner with ko by:
$$W
$$ --------------------------
$$ . . . . . . 3 . 2 . . . |
$$ . . . . X . X 1 . 4 O O |
$$ . . . . . X O O O O X O |
$$ . . . . . . X X X X . X |
$$ . . . . . . . . . . X . |
$$ . . . . . . . . . . . . |
$$ . . . . . . . . . . . . |
$$
Click Here To Show Diagram Code
[go]$$W $$ -------------------------- $$ . . . . . . 3 . 2 . . . | $$ . . . . X . X 1 . 4 O O | $$ . . . . . X O O O O X O | $$ . . . . . . X X X X . X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]
In any case thank you for your help Shaddy, I appreciate.
Wow, this position is more interesting than I thought. If black plays like that, can white just do this?

$$W
$$ --------------------------
$$ . . . . . . 3 . 2 b a . |
$$ . . . . X 5 C 1 7 4 O O |
$$ . . . . 6 X O O O O X O |
$$ . . . . . . X X X X c X |
$$ . . . . . . . . . . X . |
$$ . . . . . . . . . . . . |
$$ . . . . . . . . . . . . |
$$
Click Here To Show Diagram Code
[go]$$W $$ -------------------------- $$ . . . . . . 3 . 2 b a . | $$ . . . . X 5 C 1 7 4 O O | $$ . . . . 6 X O O O O X O | $$ . . . . . . X X X X c X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]
Then if black plays at 'a', there's another double ko at 'b' and 'c'.

Yes Kirby the black position seems not quite good. I agree with you.

Where are we?
The solution given is the following:

Click Here To Show Diagram Code: [go]$$W $$ -------------------------- $$ . . . . . 4 3 5 2 . 9 . | $$ . . . . X . X 1 . 6 O O | $$ . . . . . X O O O O X O | $$ . . . . . . X X X X 7 X | $$ . . . . . . . . . . X 8 | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

Click Here To Show Diagram Code: [go]$$Bm10 $$ -------------------------- $$ . . . . . X O O X . O . | $$ . . . . X 2 X O . X O O | $$ . . . . . X O O O O 1 O | $$ . . . . . . X X X X O X | $$ . . . . . . . . . . X X | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

white is living by double ko and we may (?) assume later the exchange

Click Here To Show Diagram Code: [go]$$Bm10 $$ -------------------------- $$ . . . . 4 X O O X . O . | $$ . . . . X O . O . X O O | $$ . . . . 3 X O O O O X O | $$ . . . . . . X X X X . X | $$ . . . . . . . . . . X X | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

Looking at all this sequence it seems to me the exchange

is not good for white.
So my first question is the following

Click Here To Show Diagram Code: [go]$$W $$ -------------------------- $$ . . . . . 4 3 . 2 . . . | $$ . . . . X 5 X 1 . . O O | $$ . . . . . X O O O O X O | $$ . . . . . . X X X X . X | $$ . . . . . . . . . . X . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

Isn't it better for white to take immediatly the ko on the left by

here above? What is the best answer for black?

Second question: seeing the result above isn't it better for black to play simply the sente yose by

Click Here To Show Diagram Code: [go]$$W $$ -------------------------- $$ . . . . . . 4 2 3 7 . . | $$ . . . . X . X 1 . . O O | $$ . . . . . X O O O O X O | $$ . . . . . . X X X X 5 X | $$ . . . . . . . . . . X 6 | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

Posted: **Mon Apr 25, 2022 2:02 pm**

https://senseis.xmp.net/?ShikatsuMyokiTsumegoSeries156

Click Here To Show Diagram Code: [go]$$W White to play and live $$ -------------------------- $$ . . . . . . . . . . . . | $$ . . . . . . . O X X . . | $$ . . . . O . . O O X X . | $$ . . . . . . . . O X O . | $$ . . . . . . X O X O O . | $$ . . . . . . . X X . O . | $$ . . . . . . . . . X O . | $$ . . . . . . . . . . X . | $$ . . . . . . . . . X . . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

It is said that the following sequence is a failure for white:

Click Here To Show Diagram Code: [go]$$W White to play and live $$ -------------------------- $$ . . . . . . . 5 3 4 1 . | $$ . . . . . . . O X X . 2 | $$ . . . . O . . O O X X . | $$ . . . . . . . . O X O 6 | $$ . . . . . . X O X O O 7 | $$ . . . . . . . X X . O . | $$ . . . . . . . . . X O . | $$ . . . . . . . . . . X . | $$ . . . . . . . . . X . . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

and black has managed to get a ko.

It is true OC.

is probably a wrong move but the moves

and

seem also wrong.

Click Here To Show Diagram Code: [go]$$W White to play and live $$ -------------------------- $$ . . . . . . . . . b 1 . | $$ . . . . . . . O X X . 2 | $$ . . . . O . . O O X X . | $$ . . . . . . . . O X O a | $$ . . . . . . X O X O O . | $$ . . . . . . . X X . O . | $$ . . . . . . . . . X O . | $$ . . . . . . . . . . X . | $$ . . . . . . . . . X . . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$ . . . . . . . . . . . . | $$[/go]

Beginning with the white move

I believe white can win the race without any condition by playing at "a" or "b". Do you agree?

Posted: **Sun Sep 29, 2024 6:27 pm**

Note added to the SL Solution page. The confusion seems to be caused by a difference in problem conventions, old and new.

Life In 19x19

Shikatsu Myoki Tsumego Series

Re: Shikatsu Myoki Tsumego Series

Re: Shikatsu Myoki Tsumego Series

Re: Shikatsu Myoki Tsumego Series

Re: Shikatsu Myoki Tsumego Series

Re: Shikatsu Myoki Tsumego Series

Re: Shikatsu Myoki Tsumego Series

Re: Shikatsu Myoki Tsumego Series

Re: Shikatsu Myoki Tsumego Series

Re: Shikatsu Myoki Tsumego Series

Re: Shikatsu Myoki Tsumego Series

Re: Shikatsu Myoki Tsumego Series

Re: Shikatsu Myoki Tsumego Series

Re: Shikatsu Myoki Tsumego Series

Re: Shikatsu Myoki Tsumego Series

Re: Shikatsu Myoki Tsumego Series