Two opening questions

hyperpape · Post by **hyperpape** » Fri Apr 06, 2012 8:20 am

I find these opening positions baffling, in spite of their apparent simplicity.

Click Here To Show Diagram Code: [go]$$c Where should white play next? $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . 2 . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . 1 . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . 6 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . 3 . . . . . 7 . . . . . 4 . . . | $$ | . . . . . . . . . . . . . 5 . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

The game progressed to here. I thought that White had to handle the moyo on the bottom, but didn't know how.

Click Here To Show Diagram Code: [go]$$c Where should White play next? $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . X O O . . | $$ | . . . O . . . . . . . X . O X X O . . | $$ | . . . , . . . . . , . . . . . X O . . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . . . . . . . . . . . . . X . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . O O # . . . . . . . . . . . . O . . | $$ | . . . X . . . . . . . . . . . . . . . | $$ | . . O X . . . . . X . . . . . O . . . | $$ | . . O X . . . . . . . . . X . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

shapenaji · Post by **shapenaji** » Fri Apr 06, 2012 12:44 pm

Actually, the upper left is more important, the invasion of the bottom can wait a bit.

Bill Spight · Post by **Bill Spight** » Fri Apr 06, 2012 1:36 pm

Click Here To Show Diagram Code: [go]$$c Where should white play next? $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . 2 . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . 1 . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 8 . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 8 . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 8 . . . . . . . . . . . . . 6 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . 3 . . . . . 7 . . . . . 4 . . . | $$ | . . . . . . . . . . . . . 5 . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

I think that White can be glad that Black did not approach the top left corner with

. I think that the large knight's enclosure is usual here. If you want to be old fashioned -- like, ancient -- you can extend on the left side. Or you could go for the mini-Chinese with the approach to the bottom left corner, but I doubt if Black will let you make a mini-Chinese.

hyperpape · Post by **hyperpape** » Fri Apr 06, 2012 2:41 pm

Bill, does that mean

is bad?

?

Post by **Joaz Banbeck** » Fri Apr 06, 2012 3:02 pm

hyperpape wrote:I find these opening positions baffling, in spite of their apparent simplicity.

Isn't that why we play go?

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Click Here To Show Diagram Code: [go]$$c The board at move 5 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . 2 . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . 1 . . . | $$ | . . c c . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . b . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . 3 . . . . . , . . . . . 4 . . . | $$ | . . . . . . . . . . . . . a . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Bill Spight wrote:...
I think that White can be glad that Black did not approach the top left corner with ...

This is a correct but short answer that could benefit from additional detail.

As Yilun Yang will tell you in his fundamentals (http://senseis.xmp.net/?FundamentalPrinciplesOfGo) , approaching an asymmetrical corner is worth more than approaching a symetrical corner. The idea behind this is that 'a' and 'b' are miai, whereas the first person to take 'c' gains something that does not have a miai-ish altenative.

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shapenaji wrote:Actually, the upper left is more important, the invasion of the bottom can wait a bit.

Shapenaji is right. But again, this idea is important enough to merit a little more discussion.

When timing an invasion, the most important question to ask is: "If I don't invade right now, can my opponent make the invasion substantially more difficult with just one move?

In it's most basic form, the question can be asked about the nisrensai.

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

If you invade right now, you are guaranteed at least a 2-space extension:

Click Here To Show Diagram Code: [go]$$Wc 2 and 3 are miai. Life is rather easy. $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . 3 . . 1 . . 2 . . . . . . | $$ | . . . X . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . |[/go]

...whereas if you let the opponent have just one move in there, the nature of the invasion is substantially different:

Click Here To Show Diagram Code: [go]$$Bc No room to extend. Run or die. $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . 3 . 2 . . 1 . . . . . . . . . | $$ | . . . X . . . . . , . . . . . X . . . | $$ | . . . . . . 4 . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . |[/go]

In the game at hand...

Click Here To Show Diagram Code: [go]$$c Where should White play next? $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . X O O . . | $$ | . . . O . . . . . . . X . O X X O . . | $$ | . . . , . . . . . , . . . . . X O . . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . . . . . . . . . . . . . X . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . O O # . . . . c d . . . . . . O . . | $$ | . . . X . . . . . . . . . . . . . . . | $$ | . . O X . . . . . X . . . . . O . . . | $$ | . . O X . . b . . . . e . X . . . . . | $$ | . . . . . a . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

...white has a handfull of invasion/reduction points. Black cannot shut them all down with one move. This is essentially a larger version of miai. If he takes one of those spots, you can still take another. So take the big shimari in the upper left.

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Implicit in both of the above comments is the idea of tedomari. There is a proverb that says "Tedomari is worth double." ( http://senseis.xmp.net/?Tedomari#toc3 ) Gaining something for yourself which the opponent can compensate for with a similar gain on his next move does not accomplish much for you. But gaining the last big play for yourself and leaving him a choice of smaller miai is great for you.

hyperpape · Post by **hyperpape** » Fri Apr 06, 2012 6:03 pm

I should say: if I were Black, I would slap a stone down in the upper left hand corner without even thinking. If I did pause to think, it would only be about whether to play high or low in light of the diagonal fuseki.

Uberdude · Post by **Uberdude** » Fri Apr 06, 2012 6:12 pm

Joaz Banbeck wrote:
Bill Spight wrote:...
I think that White can be glad that Black did not approach the top left corner with ...
This is a correct but short answer that could benefit from additional detail.

As Yilun Yang will tell you in his fundamentals (http://senseis.xmp.net/?FundamentalPrinciplesOfGo) , approaching an asymmetrical corner is worth more than approaching a symetrical corner. The idea behind this is that 'a' and 'b' are miai, whereas the first person to take 'c' gains something that does not have a miai-ish alternative.

Having said that, pros approach a 4-4 before a 3-4 in many games these days, though this is often so that the approach (if not pincered) then works as part of some formation black is building (e.g. Kobayashi, mini-chinese). The point is the two approaches aren't miai, black wants the one that works with his half of the board (though you can of course approach inside if you feel Korean). This game is a diagonal opening though so black can't make any big moyos so I agree that 5 should approach the 3-4, but it's not a huge deal.

For example with this common parallel fuseki.

Click Here To Show Diagram Code: [go]$$c The board at move 5 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . 2 . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . 1 . . . | $$ | . . g c . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . 4 . . . . . , . . . . . , 3 . . | $$ | . . . . . b . . . . . . . . a . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

In my database:

a: 1009 hits, black wins 50.9%
b: 688 hits, black wins 52.8%
c: 370 hits, black wins 54.9%
...
g: 28 hits, black wins 32.1%

So the stats say approaching at c is slightly better even though less popular than shimari at a and "wrong" approach of 4-4 first at b

Bill Spight · Post by **Bill Spight** » Fri Apr 06, 2012 6:21 pm

Joaz Banbeck wrote: Implicit in both of the above comments is the idea of tedomari. There is a proverb that says "Tedomari is worth double." ( http://senseis.xmp.net/?Tedomari#toc3 )

That proverb only applies to the end of the game tedomari.

jts · Post by **jts** » Fri Apr 06, 2012 7:28 pm

Bill Spight wrote:
Joaz Banbeck wrote: Implicit in both of the above comments is the idea of tedomari. There is a proverb that says "Tedomari is worth double." ( http://senseis.xmp.net/?Tedomari#toc3 )
That proverb only applies to the end of the game tedomari.

What about, "the difference between tedomari and the next most valuable play is worth double"?

Uberdude · Post by **Uberdude** » Sat Apr 07, 2012 1:22 am

jts wrote: What about, "the difference between tedomari and the next most valuable play is worth double"?

That's just saying the same thing with more words. The point is precise quantification doesn't make sense in the opening. If you want a proverb that applies at all stages of the game, I propose "Tedomari is awesome".

cyclops · Post by **cyclops** » Mon Apr 09, 2012 3:41 am

Bill Spight wrote:
Joaz Banbeck wrote: Implicit in both of the above comments is the idea of tedomari. There is a proverb that says "Tedomari is worth double." ( http://senseis.xmp.net/?Tedomari#toc3 )
That proverb only applies to the end of the game tedomari.

Bill, is this a typo and did you intend to write: "That proverb only applies to the end of the game." Otherwise I can't make sense, dumb as I am.

illluck · Post by **illluck** » Mon Apr 09, 2012 5:06 am

I think end of the game tedomari = tedomari at the end of the game. It's like endgame tesuji = tesuji for the endgame.

Uberdude · Post by **Uberdude** » Mon Apr 09, 2012 7:54 am

Strictly speaking, it should be "applies to end-of-the-game tedomari". It's common these days to omit the hyphens from such ad-hoc adjectives (and as a native speaker caused me no difficulty), but there is a purpose to them. I will now feel more justified when I am a grammar Nazi in the KGS kibitz.

Bill Spight · Post by **Bill Spight** » Mon Apr 09, 2012 8:19 am

cyclops wrote:
Bill Spight wrote:
Joaz Banbeck wrote: Implicit in both of the above comments is the idea of tedomari. There is a proverb that says "Tedomari is worth double." ( http://senseis.xmp.net/?Tedomari#toc3 )
That proverb only applies to the end of the game tedomari.
Bill, is this a typo and did you intend to write: "That proverb only applies to the end of the game." Otherwise I can't make sense, dumb as I am.

There are tedomari at other stages of the game. So you can talk about the last big endgame play and the last big play in the opening.

Bill Spight · Post by **Bill Spight** » Mon Apr 09, 2012 8:25 am

jts wrote:
Bill Spight wrote:
Joaz Banbeck wrote: Implicit in both of the above comments is the idea of tedomari. There is a proverb that says "Tedomari is worth double." ( http://senseis.xmp.net/?Tedomari#toc3 )
That proverb only applies to the end of the game tedomari.
What about, "the difference between tedomari and the next most valuable play is worth double"?

It's more like "Tedomari is worth a factor of two minus the ratio of the next largest play to the largest play." But really, it is simpler just to consider that each play gains what it does.

It is generally worthwhile to get the last play before the global temperature drops.

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