Confused by this

[Keith White]

https://online-go.com/puzzle/2802

I play T2 followed by S3, S3 snapback.

However, I'm likely out of my depth as even though I found the solution, I didn't think I could play a snap-back into that situation of a ponnuki, ぽんうき after he took my initial S3 stone.

Or, if I'm in a position to kill, is it allowed?
I assumed I would have to play tenuki,てぬき first?

[Javaness2]

The ko rule doesn't come into play.

in the snapback, it is true that when you put your stone on the board it has no liberties. However you remove the final liberty of white, so you kill him. No illegality is involved.

[oren]

ponnuki, ぽんうき

This is not the right hiragana for ponnuki. Normally katakana now is used for the go terms.

[Keith White]

ponnuki, ぽんうき

This is not the right hiragana for ponnuki. Normally katakana now is used for the go terms.

hmm, did I miss the double consonant ん. odd my system didn't add it.

I am surprised by the use of katakana for go considering the katakana method of 'organics/animals/fish' and that of adding 'new words' to the language.

Go is hardly new, nor it's terms. But I stand corrected if accurate.

[joellercoaster]

hmm, did I miss the double consonant ん.

Not quite...

[EdLee]

did I miss the double consonant ん

It is pon.nu.ki -- ポン抜き (ぽんぬき) --

See also ponnuki

[HermanHiddema]

ponnuki, ぽんうき

This is not the right hiragana for ponnuki. Normally katakana now is used for the go terms.

Actually, the Latin alphabet is normally used for go terms here.

[oren]

This may help.

https://ja.m.wikipedia.org/wiki/囲碁用語一覧

[Keith White]

LOL ...

OK, from what has been said, In simple terms, for me as DDK, is it correct to say...

A ponnuki shape, or in a corner etc, where 1 stone is taken and vice versa, creates an endless cycle, or could, so is KO?

So, this is not allowed.

So, multi stone shapes, where you can 'snapback' creating multiple liberties at the same time, isn't KO?

I have tried reading some stuff on this probably at my peril and it gets quite deep. Even here http://senseis.xmp.net/?KoPagesIntermediate, it's some reading so I won't assume anything until I get better.

The reason I am asking, is when playing the computer in a game, you get told, 'you cannot do that'. In problems you often don't get solutions and, or a walkthrough so that makes it hard. However, in a person to person game, I don't want to be learning something that I will have to later correct.

I never expected this to be easy...

[HermanHiddema]

Ko is really very easy: You cannot play a move which makes the position on the board exactly the same as it was before your opponent's last move. That's it.

This can only happen if your opponent took a single stone of yours, and you play on the point where that stone was, and that move captures exactly the stone that the opponent last played, but not any other stones.

This means there are exactly three basic ko shapes (corner, side, center). These might be embedded in all sorts of ways in larger shapes, but reduced to their core they are:

$$B
$$ +----------------------
$$ | a B O . . X b Y O . .
$$ | X O . . . . X O . . .
$$ | . . . . . . . . . . .
$$ | . . . X O . . . . . .
$$ | . . X c # O . . . . .
$$ | . . . X O . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .

Click Here To Show Diagram Code

[go]$$B
$$ +----------------------
$$ | a B O . . X b Y O . .
$$ | X O . . . . X O . . .
$$ | . . . . . . . . . . .
$$ | . . . X O . . . . . .
$$ | . . X c # O . . . . .
$$ | . . . X O . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .[/go]

• If white plays a, he captures exactly one stone and black cannot play at the empty point where was, because that would capture exactly one stone (at a) and return to the position before black's move.
• If white plays b, he captures exactly one stone and black cannot play at the empty point where was, because that would capture exactly one stone (at b) and return to the position before black's move.
• If white plays c, he captures exactly one stone and black cannot play at the empty point where was, because that would capture exactly one stone (at c) and return to the position before black's move.

All the other material on ko (superko, triple ko, eternal life, whatever) is so extremely rare or rule set dependent that it is not worth bothering with unless you have an interest in rules an sich.

[Bill Spight]

Ko is really very easy: You cannot play a move which makes the position on the board exactly the same as it was before your opponent's last move. That's it.

{snip}

All the other material on ko (superko, triple ko, eternal life, whatever) is so extremely rare or rule set dependent that it is not worth bothering with unless you have an interest in rules an sich.

Some of us like to think of ko as Ding-Dong an sich.