Why white doesn't connect here?


#1

Hello everyone, I hope I’m posting this in the right category.

I’m reading a Go beginners book (Janice Kim’s Learning to play go) and it has this diagram: http://i.imgur.com/PVKe9Th.png (there are no diagrams after those two). From what I understand, right after white 2 captures black, black can’t play again on that same spot because of the ko rule which means that black has to play elsewhere on the board but is there a reason why white can’t connect all the white stones at the top when it’s her turn again? The diagram implies that white couldn’t do anything else to protect those 5 stones that black 3 captures. I’m still getting my head around the game so I may be missing something very basic here…


#2

The Ko rules only apply to the same board position.

In other words, you can’t make the board look exactly as it was before your opponent played.

Because black would be capturing 5 white stones the board position would not look the same. So the Ko rule wouldn’t apply here.

To give you a better picture. Ko was invented in order to ensure games couldn’t go on forever. i.e. Capturing back and forth, without any game progression.

Because capturing the 5 stones eliminates the possibility of this happening, the Ko rule doesn’t apply.

I hope that makes sense.

EDIT: I also made this Demo: https://online-go.com/demo/view/248159

I hope it helps.


#3

Thanks for the reply _Thrawn but my question isn’t why black 3 can capture, it can for the reasons you mentioned. My question is why white doesn’t connect the 5 stones before black can play in that position again? After black plays elsewhere because of the ko rule white can play in that spot and connect the stones (unless I’m missing something, which is what I want to find out), why doesn’t it?


#4

Thrawn is absolutely correct. It has nothing to do with ko in this instance. This is a snapback technique. It is essentially sacrificing/ “throwing in” a stone to put an already surrounded group in atari. Snapback and atari are similar in its relationships, except that you cannot recover/save those endangered stones/groups, while with atari, you could (stones, not groups).
For the diagram, after white captures, it is black’s turn to play. White captures black, which puts those stones in atari (one liberty). If, for instance, black decided to play elsewhere instead of capturing said stones (the original 5 stones in atari), then white can connect the two groups. Ko would be something like this:

You can see that black plays next (2) and captures white stone (1). White plays elsewhere because of the ko rule, and black can either play in the place where the original white stone was located to solidify its group, or play elsewhere, allowing white to capture stone (2).

Here is further reading on both:
http://senseis.xmp.net/?Ko
http://senseis.xmp.net/?Snapback


#5

I see it now. So what you’re saying is that ko doesn’t happen in those diagrams right? If that’s the case then I don’t understand the ko concept as well as I thought, I’ll check out those links. Thanks everyone!


#6

No problem man. Ko is so simple, but applying it during a game effectively makes it very complicated. You have SDK (single digit kyu) and even some Dan level players who still aren’t able to grasp the concept effectively, much like the game of go itself, simple, yet hard to master. You are definitely on the right track. Learn to Play Go series (currently on book 3 myself) is an excellent series. Keep grinding on this server and maybe join 1+ more servers when you get better so you can have a versatile playing experience . Keep reading, watch and play games, study those and other’s games, and do plenty of go problems. Good luck.


#7

Thanks o000o00o, since I have quite an aerial knowledge of fuseki (I think that’s the name) I’m just playing 13x13 games in my phone right now. I’m hoping the book deals with that eventually, or maybe there are better online resources for that? I’d be interested to know. Seems like a lot of game sequences are generally understood by everyone but I just don’t get them, so whenever I watch a game here I’m up in the clouds because of my low level of knowledge.


#8

Everything’s been explained already, but just for brevity:

A Ko is about capturing a SINGLE stone. If it’s more than one stone then it’s not a Ko.


#9

Thanks trohde! That simplification is very helpful.