This is the opening of a recent game:
What should white play now? Should white take the big point near (a), or should white do some reducing? If white wants to reduce the bottom right, how should white do it?
Let say white plays at (a), and then black encloses the corner, leading to the following. What should white do next? If white wants to reduce the lower right now, what are some possibilities?
Thanks.
In the actual game, black made a mistake by playing a small move after I played at (a). So I still had a chance to reduce black in the lower right by playing a one-space high approach. I probably did it wrong in subsequent moves, though, as I failed to make any strong shape. I got away only because black decided to sacrifice the left-middle stone when I pincher at (b) later.
Question of opening/reducing
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Solomon
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Re: Question of opening/reducing
If I was Black and it was my turn, I would love to play here to expand my moyo:
But it's White's turn, so by following the proverb that my enemy's key point is my key point, I would play here to expand my moyo:
Is it the only move? No. But it's simple and effective.
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Abyssinica
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skydyr
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Re: Question of opening/reducing
Which one?Abyssinica wrote:Tenen may be too far; how about a 9-9 point?
I think A is not quite as good, because black can easily take tengen anyways and leave white more cramped. B and D feel at least somewhat miai, white taking D to build or B to destroy, and black taking the other to do the same thing. C feels a little far, but that doesn't mean it's wrong. My gut instinct for C as compared to tengen is that it's more geared to turning the center into dame through fighting. It's more loosely connected to white's formation, so it becomes easier for black to invade, and being closer to black's strong position, it has less maneuvering room.
In any case, I feel the next big point is going to be in the vicinity of E, which will probably be sente or sente-ish for black.
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Uberdude
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Re: Question of opening/reducing
Another plausible choice for white, if he feels territorial, is as below:
To stop this, black will often approach the lower left rather than simply extending.
Answering at 10 is a good simple choice, but white could also pincer to resist black's plan.
The downside of my suggestion is black can go for a moyo, but I don't fear that:
If black makes a shimari with 13 white could think about moves like a-e. Black might play 13 more ambitiously with something like below but white has plenty of things to aim at like a-d (notice c has attacking power):
To stop this, black will often approach the lower left rather than simply extending.
Answering at 10 is a good simple choice, but white could also pincer to resist black's plan.
The downside of my suggestion is black can go for a moyo, but I don't fear that:
If black makes a shimari with 13 white could think about moves like a-e. Black might play 13 more ambitiously with something like below but white has plenty of things to aim at like a-d (notice c has attacking power):
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gostudent
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Re: Question of opening/reducing
I am under the impression that three-space extension is often bad, because of the potential invasion of (c) or (d) (and in this case, that would also be corner approach). For the top right corner, I am not afraid because I have entering 3-3 as emergency option, but here I am less sure.Uberdude wrote:Another plausible choice for white, if he feels territorial, is as below:
What should white do if black invades at (c) or (d)? Thanks.
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EdLee
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Hi GoStudent, you want to get rid of this kind of thinking immediately.gostudent wrote:I am under the impression that three-space extension is often bad, ...
It all depends on the local and global contexts.
For example:
If you're worried about the gap between
and 
,then what about the even bigger gap between
and 
?Or between
and 
? Between and 
?Between
and 
?Some ways to improve your understanding of these shapes:
play games, review them, and study the variations.
For example, you asked about B's invasion between
and --that's a good question.
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Uberdude
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Re: Question of opening/reducing
First of all, you should realize that while 10 is a 3 space extension, that is not its primary purpose; that is to undermine the 4th line black stone of 9.gostudent wrote: I am under the impression that three-space extension is often bad, because of the potential invasion of (c) or (d) (and in this case, that would also be corner approach). For the top right corner, I am not afraid because I have entering 3-3 as emergency option, but here I am less sure.
What should white do if black invades at (c) or (d)? Thanks.
Next is to appreciate the big difference between a 3 space extension from 3rd to 4th line and one from 3rd to 3rd or 4th to 4th. The former has much better connectivity, as shown in the diagram below. In the latter you can usually connect by attaching and sacrificing a stone, but that is costly.
The next important thing is the presence of the opponents stones, particularly as checking extensions. These make the invasion more difficult to deal with as they are a friendly stone for your opponent to connect to and mean you can't extend to make eyespace on the side.
So perhaps a better "proverb" would be:
Let's look at some examples:A 3 space extension on the 3rd line has poor connectivity, so if you want to be connected you should only do it if you have a good plan to deal with the invasion.
Here white is in black's sphere of influence with a strong shimari below (black already has checking extensions both sides), so a 3 space extension is not a good idea as white doesn't want to make 2 groups but stay connected and settle his one stone. So a 2 space extension is better.
However here black has just a 4-4 below, so white's jump out is pretty much sente*, which then allows the kosumi of 7 to more-or-less connect (black could then play a which threatens to push at b and cut with black having the tesuji of c to make miai to connect above or below, so it is honte for white to answer a at b.
*If black doesn't answer white is happy to build influence on the lower side and later could save 1 or use its aji with e.g. z.
Sometimes we don't mind being disconnected as we have space to extend. Here white extends 3 spaces with 3 and if black invades just calmly makes a 2 space extension to settle the lower stone (note this is not a 3 space because we don't want to get split now, like above). Black might then follow up on 1 with a/b and white might continue there, or more likely at this stage of the opening, tenuki to a bigger area.
As a variation on the above, if black doesn't have a shimari at the bottom right white could think about making a 2nd 3 space (2 is still good and simple) though it could get rather crazy complicated. Simple is for black to answer with shimari and then white defends the gap.
Or things could go crazy. (I would only recommend doing this when you are dan level.)
As you say, another way to deal with the invasion is sacrificing one stone and using it to jump into 3-3. Now in your board if black invaded at the top white should probably attach on top as it's a 3rd to 4th line 2 space extension with good connectivity, but if k16 was at k17 then 3-3 makes more sense.
So back to your question, my first thought is to attach and stay connected. Black can wedge with 13 because he has the ladder (to top right if white ataris from below and connects to left). Black gets the corner, but white gets a strong wall that contributes to his growing left side moyo, and also k4 has become rather weak. I prefer white as black is ruining his own moyo prospects with giving white such thickness.
Another idea is to jump to the key point that black would like to have got and start a big running fight. But now white wants to play at a and b, so while might be able to play b and then cut at the waist if black a as black doesn't have the ladder, this is a complicated fight so I would recommend the simple attach of before.
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Bill Spight
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Re: Question of opening/reducing
In a similar position Go Seigen commented on this line of play.
White is not bad, he said.
White is not bad, he said.
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
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gostudent
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Re: Question of opening/reducing
Thank you for Uberdude detailed explanation, and Bill's suggestion of a possible reduction technique.
And thank you for EdLee's thoughts as well -- I would learn more when I consider specific stone settings, since the right answer differs depending on the setting.
And thank you for EdLee's thoughts as well -- I would learn more when I consider specific stone settings, since the right answer differs depending on the setting.
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Joelnelsonb
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Re: Question of opening/reducing
I'm certainly no expert but I can tell you that I once saw a Nick Sibbicky lesson where he states that if you're below 5 kyu then you shouldn't ever take the tengen unless its extremely obvious you should do so (such a blocking an atari or something) because beginners almost always play it at the wrong time. This being said, I would imagine that playing anywhere in the center at the given time of the example would be premature and ultimately pointless.
Thinking like a go player during a game of chess is like bringing a knife to a gun-fight. Thinking like a chess player during a game of go feels like getting knifed while you're holding a gun...
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Solomon
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Re: Question of opening/reducing
Judging the merit of a move off a rule of thumb dependent on the level of the player making the move is silly.Joelnelsonb wrote:I'm certainly no expert but I can tell you that I once saw a Nick Sibbicky lesson where he states that if you're below 5 kyu then you shouldn't ever take the tengen unless its extremely obvious you should do so (such a blocking an atari or something) because beginners almost always play it at the wrong time. This being said, I would imagine that playing anywhere in the center at the given time of the example would be premature and ultimately pointless.
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Abyssinica
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Re: Question of opening/reducing
Araban wrote:Judging the merit of a move off a rule of thumb dependent on the level of the player making the move is silly.Joelnelsonb wrote:I'm certainly no expert but I can tell you that I once saw a Nick Sibbicky lesson where he states that if you're below 5 kyu then you shouldn't ever take the tengen unless its extremely obvious you should do so (such a blocking an atari or something) because beginners almost always play it at the wrong time. This being said, I would imagine that playing anywhere in the center at the given time of the example would be premature and ultimately pointless.
When a 15k plays a weird move, we assume he's just bad.
When a 9p plays that same weird move, we assume he's profound and knows much more about the game than we do.
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EdLee
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Yes. That's based on our experience and statistics.Abyssinica wrote:When a 15k plays a weird move, we assume he's just bad.
When a 9p plays that same weird move, we assume he's profound and knows much more about the game than we do.
If you jump off a tall building, experience and statistics tell us most likely you'll die. But there's some non-zero probability that some huge wind or a giant balloon may save your life.
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illluck
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Re:
What.EdLee wrote:Yes. That's based on our experience and statistics.Abyssinica wrote:When a 15k plays a weird move, we assume he's just bad.
When a 9p plays that same weird move, we assume he's profound and knows much more about the game than we do.
If you jump off a tall building, experience and statistics tell us most likely you'll die. But there's some non-zero probability that some huge wind or a giant balloon may save your life.