Life In 19x19
http://www.lifein19x19.com/

Does this have a name?
http://www.lifein19x19.com/viewtopic.php?f=11&t=7956
Page 1 of 1

Author:  PeterPeter [ Sun Feb 24, 2013 5:03 am ]
Post subject:  Does this have a name?

Click Here To Show Diagram Code
[go]$$B
$$ | . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . O O O . .
$$ | . . X X X . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .[/go]

Does this common gap of stones at the edge of a board have a name?

I would like to be able to call it something while I am experimenting with it, and also find out a bit more about it online.

Thanks.

Author:  lobotommy [ Sun Feb 24, 2013 5:13 am ]
Post subject:  Re: Does this have a name?

No.

Author:  EdLee [ Sun Feb 24, 2013 5:27 am ]
Post subject: 

Peter, You mean for studying the end game? That's a good one to study. Here's another (simpler):
Click Here To Show Diagram Code
[go]$$B
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . O O O O O O
$$ | . X X X X X X
$$ | . . . . . . .
$$ | . . . . . . .[/go]

Author:  PeterPeter [ Sun Feb 24, 2013 5:33 am ]
Post subject:  Re: Does this have a name?

I think I am OK with the 1 point gap.

The first time I came across the 2 point gap, I dived straight in with, "If one hane is good, double hane must be better". It did not end well.

Author:  Amelia [ Sun Feb 24, 2013 5:45 am ]
Post subject:  Re: Does this have a name?

PeterPeter wrote:
The first time I came across the 2 point gap, I dived straight in with, "If one hane is good, double hane must be better". It did not end well.

Yeah :lol:
There are other nasty things to consider, like for example this one (if one of the players descends and the other does not): http://senseis.xmp.net/?MonkeyJump
Beware of it. Our fellow DDKs love this tesuji, as it is simple to remember and can eat quite a bit of enemy territory in the endgame.

Author:  PeterPeter [ Sun Feb 24, 2013 6:09 am ]
Post subject:  Re: Does this have a name?

Monkey jumps are great fun if your opponent allows you to do one, but assuming they reply properly and close it off, it feels like there should be something better available than allowing it to become Ed's position:

Click Here To Show Diagram Code
[go]$$B
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . O O O O O O
$$ | . X X X X X X
$$ | . . . . . . .
$$ | . . . . . . .[/go]

Author:  lemmata [ Sun Feb 24, 2013 8:40 am ]
Post subject:  Re: Does this have a name?

Hi Peter. This might be normal. One hane is sente end game.
Click Here To Show Diagram Code
[go]$$B
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . 4 . . . .
$$ | . 2 . . . . .
$$ | . 1 O O O O O
$$ | . 3 X X X X X
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .[/go]

Solid connection (instead of the tiger's mouth) allows black to get another sente end game move.
Sente:
Click Here To Show Diagram Code
[go]$$B
$$ | . . . . .
$$ | 6 8 . . . . .
$$ | 5 O O . . . .
$$ | 7 X O O O . .
$$ | . X X X X . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .[/go]

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

If white doesn't respond to black 3, then black has good follow ups.
More sente reduction:
Click Here To Show Diagram Code
[go]$$B
$$ | 4 6 . . .
$$ | 3 2 . . . . .
$$ | 1 O . . . . .
$$ | 5 X O O O . .
$$ | . X X X X . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .[/go]

Depending on the surrounding stones, this clamping move might cause some trouble when white plays away after black's connection.
Click Here To Show Diagram Code
[go]$$B
$$ | . . . . .
$$ | . 1 . . . . .
$$ | . O . . . . .
$$ | . X O O O . .
$$ | . X X X X . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .[/go]

Is it possible that black can attack white like this?
Click Here To Show Diagram Code
[go]$$B
$$ | . . . . .
$$ | . 1 3 . 5 . .
$$ | 2 O 4 . . . .
$$ | . X O O O . .
$$ | . X X X X . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .[/go]

Then white may not be able to play the descent at :w2:, which means that black will be able to connect underneath.


This sort of hane is good to play even in the opening (EDIT: Not always but often! There are few absolutes in go). Think about some common joseki:
Joseki:
Click Here To Show Diagram Code
[go]$$B
$$ | . . 4 . . . .
$$ | . 2 . . . . .
$$ | . 1 O O . . .
$$ | . 3 X X O O O
$$ | . . . . X X .
$$ | . . . . . . .
$$-----------[/go]


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

Joseki:
Okay, this last one is not the same as the other ones, but the shape is similar.
Click Here To Show Diagram Code
[go]$$B
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . 8 . . .
$$ | . . 4 . . . .
$$ | . . X 2 O 6 .
$$ | . . 5 3 1 . 7
$$ | . . . . . . .
$$ | . . . . . . .
$$-----------[/go]

Author:  Bill Spight [ Sun Feb 24, 2013 9:15 am ]
Post subject:  Re:

EdLee wrote:
Peter, You mean for studying the end game? That's a good one to study. Here's another (simpler):
Click Here To Show Diagram Code
[go]$$B
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . O O O O O O
$$ | . X X X X X X
$$ | . . . . . . .
$$ | . . . . . . .[/go]


I think that it is very difficult, even for dan players. This one is easier, but still difficult.

Author:  PeterPeter [ Sun Feb 24, 2013 9:23 am ]
Post subject:  Re: Does this have a name?

From this position:
Click Here To Show Diagram Code
[go]$$B
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . 2 . . . . .
$$ | a 1 O O O O O
$$ | . b X X X X X
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .[/go]

...I had been looking at 'a' as the natural follow-up.

From here:
Click Here To Show Diagram Code
[go]$$B
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | 4 2 c . . . .
$$ | 3 1 O O O O O
$$ | . d X X X X X
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .[/go]

If Black can invade at 'c', and not get captured by one individual White move, he can capture :w2: and :w4: .

More likely though is that Black will have to play at 'd' to stop white playing there and capturing :b1: and :b3: .

Is this why 'b' is better than 'a': because 'a' ends in gote?

Author:  SoDesuNe [ Sun Feb 24, 2013 9:38 am ]
Post subject:  Re: Does this have a name?

For me the natural follow-up to a Hane on the second line is connecting, otherwise the intial Hane might get captured.
Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | c 2 d . . . .
$$ | a 1 O O O O O
$$ | . b X X X X X
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .[/go]

That's why extending downwards to 'a' is not good in most cases because the cutting point at 'b' remains. So any play from White at 'c' is forcing you to defend at 'b' if you don't want to lose your stones. In other words you turn 'c' into Sente for White, which is generally unwanted in the endgame. If this border on the other hand is the last play on the board then descending to 'a' is the correct play because it will give you one more point compared to just connecting at b.
Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | 4 2 a . . . .
$$ | 3 1 O O O O O
$$ | . b X X X X X
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .[/go]

Note that 'a' never works after you extended downwards. White just plays 'b' and captures your stones. It's two liberties for White against one liberty for you.

Since we mentioned Sente in the endgame: In my experience in most cases Black will want to play like this because he can keep Sente while finishing off this border (depends of course on the whole board, e.g. the remaining endgame). If White does not answer :b1: , Black can play at :w6: or monkey-jump at 'a', which is big.
Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | a . . . . . .
$$ | 4 6 . . . . .
$$ | 3 2 O O O O O
$$ | 5 1 X X X X X
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .[/go]

Author:  Bill Spight [ Sun Feb 24, 2013 9:46 am ]
Post subject:  Re: Does this have a name?

PeterPeter wrote:
From this position:
Click Here To Show Diagram Code
[go]$$B
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . 2 . . . . .
$$ | a 1 O O O O O
$$ | . b X X X X X
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .[/go]

...I had been looking at 'a' as the natural follow-up.

From here:
Click Here To Show Diagram Code
[go]$$B
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | 4 2 c . . . .
$$ | 3 1 O O O O O
$$ | . d X X X X X
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .[/go]

If Black can invade at 'c', and not get captured by one individual White move, he can capture :w2: and :w4: .

More likely though is that Black will have to play at 'd' to stop white playing there and capturing :b1: and :b3: .

Is this why 'b' is better than 'a': because 'a' ends in gote?


No. They are both gote. :)

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


Black needs to reply at 5. Why?

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


Because White threatens this capture. If :b4: captures at 5, :w5: takes back at 1. That is called a snapback. The position after the exchange of the :bc: and :wc: stones is better for White than the original position, because in the original position White cannot continue with :w3:. That is why Black needs to connect with :b5: in the previous diagram. If he doesn't he has just lost points for nothing.

Compare these positions.

Click Here To Show Diagram Code
[go]$$B
$$ | . . . . . . . _ . . . . . . . |
$$ | . . . . . . . _ . . . . . . . |
$$ | . . . . . . . _ . . . . . . . |
$$ | . . . . . . . _ . . . . . . . |
$$ | W O . . . . . _ . . . . . X . |
$$ | B X O O O O O _ X X X X X O . |
$$ | . B X X X X X _ O O O O O W . |
$$ | . . . . . . . _ . . . . . . . |
$$ | . . . . . . . _ . . . . . . . |
$$ | . . . . . . . _ . . . . . . . |
$$ | . . . . . . . _ . . . . . . . |
$$ | . . . . . . . _ . . . . . . . |[/go]


The two sides of the board are independent. :)

Click Here To Show Diagram Code
[go]$$B
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . 2 . . . . .
$$ | a 1 O O O O O
$$ | c b X X X X X
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .[/go]


Now. What about "c"? :)

Author:  Uberdude [ Sun Feb 24, 2013 10:44 am ]
Post subject:  Re: Does this have a name?

SoDesuNe wrote:
For me the natural follow-up to a Hane on the second line is connecting,


That's because you are not a beginner. It is a very common beginners mistake, indeed perhaps what the majority do. I know that when I was a beginner I did it too*. Probably because to the beginner eye it looks like you are getting a bigger area than with the solid connect. But that's overlooking the sente gain/loss that can happen later so actually it is smaller.

* Actually looking back at my DDK games on KGS it seems I was a big fan of the 1st line hanging connection, which in general terms** is not as bad as the descent, but worse than the solid connection.

** There are of course certain situations in which the 1st line descent, 1st line hanging connection, 2nd line solid connection, and 2nd line hanging connection are the best move.

Author:  Bill Spight [ Sun Feb 24, 2013 10:59 am ]
Post subject:  Re: Does this have a name?

Uberdude wrote:
SoDesuNe wrote:
For me the natural follow-up to a Hane on the second line is connecting,


That's because you are not a beginner. It is a very common beginners mistake, indeed perhaps what the majority do. I know that when I was a beginner I did it too*. Probably because to the beginner eye it looks like you are getting a bigger area than with the solid connect. But that's overlooking the sente gain/loss that can happen later so actually it is smaller.

* Actually looking back at my DDK games on KGS it seems I was a big fan of the 1st line hanging connection, which in general terms** is not as bad as the descent, but worse than the solid connection.

** There are of course certain situations in which the 1st line descent, 1st line hanging connection, 2nd line solid connection, and 2nd line hanging connection are the best move.


When I was a beginner I recoiled from the descent. But I was confused about whether to play the solid connection or the hanging connection. It turns out that, when it is not a matter of tactics, the hanging connection is dominant, unless the difference in ko threats matters. It will rarely matter, but I think that the gain regarding ko is both more frequent and larger than the gain from preventing the hane-and-connect. :)

Author:  Phelan [ Sun Feb 24, 2013 8:12 pm ]
Post subject:  Re: Does this have a name?

PeterPeter wrote:
From this position:
Click Here To Show Diagram Code
[go]$$B
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . 2 . . . . .
$$ | a 1 O O O O O
$$ | . b X X X X X
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .[/go]

...I had been looking at 'a' as the natural follow-up.

From here:
Click Here To Show Diagram Code
[go]$$B
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | 4 2 c . . . .
$$ | 3 1 O O O O O
$$ | . d X X X X X
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .[/go]

If Black can invade at 'c', and not get captured by one individual White move, he can capture :w2: and :w4: .

More likely though is that Black will have to play at 'd' to stop white playing there and capturing :b1: and :b3: .

Is this why 'b' is better than 'a': because 'a' ends in gote?

There's another problem I've seen with descending, and that a lot of my opponents don't seem to thing about.
Click Here To Show Diagram Code
[go]$$B
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . 2 . . . . .
$$ | 3 1 O O O O O
$$ | . . X X X X X
$$ | . 4 . . . . .
$$ | . . . . . . .
$$ | . . . . . . .[/go]


This :w4: doesn't work here, but if there's weakness on the lower part, this peep might be a lot of trouble. It's rarer than what has been shown so far, but it's another reason why I usually prefer to play the solid connection.

Page 1 of 1 All times are UTC - 8 hours [ DST ]
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
http://www.phpbb.com/