Gochild's opening problems

Koroviev · #1

Hi all,

I've been looking at the opening probs on Gochild, which offer you a choice of three or four moves and ask you to choose the single 'correct' one. I am pretty lost on all but the simplest, and there is no explanation of why the move is wrong.

I was wondering how 'absolute' stronger players think these moves are? Are the 'correct' answers just inarguably obvious to you? To my weak eyes they all look very close in terms of value - not like life and death or even the joseki problems, where I can clearly see the good moves and the bad.

I suppose I find these problems a little troubling, since I can't fathom the reasons for the answers myself, and I'm unsure on what authority they are given. Do they look like sensible problems to others?

http://gochild2009.appspot.com/

topazg · #2

I've just had a quick go at this set, and out of the first 20, I got 19 right, and accept the mistake I made on the other. Out of the first 10, I'd consider the "correct" option absolutely better than the others, and while there are flavour issues, I would say I agree with all of the next 10 as being the better move.

That said, I'm not strong enough to assess them in any great detail, and my rank is therefore my caveat, but most of these come from high level (author) problem packs, and the site author is a very strong Chinese amateur from memory (Chinese 5 or 6 dan).

Chew Terr · #3

When I did those problems, I felt that they tended to be one of three types:
One of your groups is weak, defend it!
An opponent group is weak, pressure it!
No groups are weak. Play at the boundary of two frameworks! I explained this concept a little, recently, here: viewtopic.php?p=37949#p37949

Try going back and looking at any questions you weren't sure on. Check if the correct answer matches any of these. From my remembered experience, I wouldn't be surprised if most do. Additionally, when solving new problems, try to keep these sort of ideas in mind. If your opponent gets to attack a weak group early, it's a huge boon that can carry him or her through the game. The same is true for your own attacks. And boundary plays are huge, because they harm your opponent as much as they help you, and they are often sente to boot.

Bill Spight · #4

Koroviev wrote:

Hi all,

I've been looking at the opening probs on Gochild, which offer you a choice of three or four moves and ask you to choose the single 'correct' one. I am pretty lost on all but the simplest, and there is no explanation of why the move is wrong.

I was wondering how 'absolute' stronger players think these moves are? Are the 'correct' answers just inarguably obvious to you? To my weak eyes they all look very close in terms of value - not like life and death or even the joseki problems, where I can clearly see the good moves and the bad.

I suppose I find these problems a little troubling, since I can't fathom the reasons for the answers myself, and I'm unsure on what authority they are given. Do they look like sensible problems to others?

http://gochild2009.appspot.com/

I don't think you can find many absolute answers in the opening, except the glaringly obvious: e. g., don't play on the first line unless it is necessary (huge).

Still, opening theory has been developing for centuries, and we are pretty sure about a lot of things. Still, opinions change, and some plays that were supposedly bad when I was learning go are now played every day.

Edit: BTW, I went to the site and was unable to get any go content than an empty 13x13 board. Even after enabling pop-up windows. {shrug}

Numsgil · #5

@Bill:

You have to chose a 'pack' from the right hand window. Openings are under 'Intermediate'. Then you have to click the 'question' tab that appears (next to the 'pack' tab) and select a question.

quantumf · #6

If you're referring to the intermediate set of opening problems, then I would say they're all applications of basic opening principles, such as Urgent Before Big (i.e. defend weak groups), Play on the Boundary of Two Moyos, Play Away From Thickness, and so on. Also some lesser principles, such as Don't Get Sealed In, Separate Opponent Groups and Take Away Your Opponent's Base

Dusk Eagle · #7

I had Bill's problem too, but Numsgil's advice solved it.

quantumf wrote:

If you're referring to the intermediate set of opening problems, then I would say they're all applications of basic opening principles, such as Urgent Before Big (i.e. defend weak groups), Play on the Boundary of Two Moyos, Play Away From Thickness, and so on. Also some lesser principles, such as Don't Get Sealed In, Separate Opponent Groups and Take Away Your Opponent's Base.

This is exactly it. The fewer of these concepts you understand, the less this problem set is likely to help, without additional commentary.

Click Here To Show Diagram Code: [go]$$B $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . O . . . | $$ | . . . , . . . . . , . . . . . , O . . | $$ | . . . X . . a . O . b . . X . X O . . | $$ | . . . . . . . . . . . . . . . . X O . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

For instance, 'a' or 'b'? At first, it may seem like 'a' is the correct answer. After all, it is making an extension from a shimari. Isn't that a good thing?

Well, it is, but let's look at how that will develop.

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

Black has a problem forming. His group on the right is suddenly very weak. White will have an easy time terrorizing it for profit. At the very least, he'll probably be able to make some territory along the right edge.

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

With this move however, all of black's groups are strong. White will be hard pressed to find anywhere to attack: in fact, it might be him that comes under attack later.

When you consider things like that, it's easier to understand the correct move. But, as the problem set is not willing to explain that to you, it might be easier to focus more on life and death problems, where the answer is more clear-cut. If you want to improve your opening, you could try a book like Opening Theory Made Easy by Otake Hideo (one of the few theory books I've ever read).

You should also try to understand the strength of the groups on the board: if one of your groups is weak, defend it, if one of your opponent's groups is weak, attack it, otherwise, play a big move. This does, however, take some experience to recognize.

Bill Spight · #8

Thanks to Numsgil, I found the problems. I think that you can trust that, among the options provided, the answer is best. (There may be a better move that is not an option, however.)

I did find one that I disagreed with. It relates to some recent discussions here, so here it is.

Click Here To Show Diagram Code: [go]$$ Black to play $$ -------------------------- $$ | . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . | $$ | . . . O X . . a b c . . . | $$ | . . O , X . , . . , . . . | $$ | . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . | $$ | . . . , . . , . . , . . . | $$ | . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . | $$ | . . . , . . , . . , . . . | $$ | . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . | $$ ---------------------------[/go]

As we know, the proverb says to extend to "b". However, I think that on the 13x13 "c" is better, because of the corner.

(I suspect that this was originally a 19x19 position, but got scrunched down to 13x13, without much thought.)

Thunkd · #9

Koroviev, why don't you post a problem that you feel you just didn't understand, and try to defend why you chose the move that you originally chose. We can discuss which move looks best to the rest of us and why. Perhaps that will help you understand why certain moves were put forward as the correct move, and why your move might not be the best choice.

Numsgil · **#10**

Bill Spight wrote:

As we know, the proverb says to extend to "b". However, I think that on the 13x13 "c" is better, because of the corner.

(I suspect that this was originally a 19x19 position, but got scrunched down to 13x13, without much thought.)

Interesting, because most of the opening problems I see on the site are on 19x19 boards. Which question number specifically was it (if you can find it again)?

Bill Spight · **#11**

Numsgil wrote:

Bill Spight wrote:

As we know, the proverb says to extend to "b". However, I think that on the 13x13 "c" is better, because of the corner.

(I suspect that this was originally a 19x19 position, but got scrunched down to 13x13, without much thought.)

Interesting, because most of the opening problems I see on the site are on 19x19 boards. Which question number specifically was it (if you can find it again)?

61 or 62, I think. (I had the strange experience of apparently clicking on a question and having a different question appear.

)

Numsgil · **#12**

Bill Spight wrote:

Numsgil wrote:

Bill Spight wrote:

As we know, the proverb says to extend to "b". However, I think that on the 13x13 "c" is better, because of the corner.

(I suspect that this was originally a 19x19 position, but got scrunched down to 13x13, without much thought.)

Interesting, because most of the opening problems I see on the site are on 19x19 boards. Which question number specifically was it (if you can find it again)?

61 or 62, I think. (I had the strange experience of apparently clicking on a question and having a different question appear.

)

Hmm, it does seem to be 13x13 on purpose. The problems around it in the list are all 19x19.

Koroviev · **#13**

Wow, lots of great responses, thanks. It's hard to now how seriously to take the problems you stumble across online, but know I know they are considered sound, I can happily agonise over my failure to understand them.

quantumf wrote:

I would say they're all applications of basic opening principles, such as Urgent Before Big (i.e. defend weak groups), Play on the Boundary of Two Moyos, Play Away From Thickness, and so on. Also some lesser principles, such as Don't Get Sealed In, Separate Opponent Groups and Take Away Your Opponent's Base

I'm familiar with all those principles (doesn't mean I can use them, of course!) except for playing on boundaries, which I will look into (thanks for your link, Chew Terr).

I think my main problem with these problems is my definition of safe groups - basically, unless a group is in atari or about to be severely cut, I tend to abandon it and play a big point. These problems - and the comments in this thread - are leading me to look at this kind of thing quite differently.

@Dusk Eagle - thanks for your analysis of that problem, it would be nice if the site provided such an exhaustive answer for each Q. ;-)

Numsgil · **#14**

Koroviev wrote:

I think my main problem with these problems is my definition of safe groups - basically, unless a group is in atari or about to be severely cut, I tend to abandon it and play a big point. These problems - and the comments in this thread - are leading me to look at this kind of thing quite differently.

If the group in question is a single stone, you might be able to sacrifice it effectively, if you can't make a base for it and running doesn't afford you opportunity to counterattack (because groups on either side of it are too strong, or you have another weak group to tend). But if there's more than a single stone and/or you can create a base for it, that's an urgent move and trumps any big moves.

For your edification, some positions and ideas about weak groups:

This white group is in danger, and needs to run. 'a' or 'b' are the usual points (I would prefer 'a' here since 'b' is playing near black's thickness). It's not quite urgent, but it's definitely pretty important.

Click Here To Show Diagram Code: [go]$$W $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . X . . X . O . . O . X . . . . | $$ | . . . , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . a . . b . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . |[/go]

White is in danger here, but there isn't an effective way to counter attack, and living locally is doubtful, so white should look for ways to sacrifice this stone to get free moves elsewhere. That is, white needs to treat this stone lightly, as aji in black's position.

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

Similar position, but white has too many stones to sacrifice (it's a pretty silly position, of course). It's a weak group that white has to tend to. It's urgent to make a running move to try and save this group right now this very instant.

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

White needs to make a move here to form a base. It's urgent. If black plays here, white has no base. Making a move on the other side, at around 'a', would be the wrong direction, because it forces black towards white's weak stone. Which might work if white plans to sacrifice that lone stone, but that's probably not a good idea here.

Click Here To Show Diagram Code: [go]$$W $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . X . 1 . . O . . . X . . . . | $$ | . . . a . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . |[/go]

Almost identical position, but white's stone and black's lone stone are in a different position. A move at 'a' is an inducing move: white gets to force black to force white to make a move white wants to play anyways (might not be the best move here, but it illustrates the idea).

Click Here To Show Diagram Code: [go]$$W $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . X . . 2 . O . . 3 . X . . . . | $$ | . . 1 . . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . |[/go]

Stronger players might quibble with these diagrams, but I hope that's at least partially useful.

Bill Spight · **#15**

Numsgil wrote:

Koroviev wrote:

I think my main problem with these problems is my definition of safe groups - basically, unless a group is in atari or about to be severely cut, I tend to abandon it and play a big point. These problems - and the comments in this thread - are leading me to look at this kind of thing quite differently.

If the group in question is a single stone, you might be able to sacrifice it effectively, if you can't make a base for it and running doesn't afford you opportunity to counterattack (because groups on either side of it are too strong, or you have another weak group to tend). But if there's more than a single stone and/or you can create a base for it, that's an urgent move and trumps any big moves.

For your edification, some positions and ideas about weak groups:

This white group is in danger, and needs to run. 'a' or 'b' are the usual points (I would prefer 'a' here since 'b' is playing near black's thickness). It's not quite urgent, but it's definitely pretty important.

Click Here To Show Diagram Code: [go]$$W $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . X . . X . O . . O . X . . . . | $$ | . . . , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . a . . b . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . |[/go]

White is in danger here, but there isn't an effective way to counter attack, and living locally is doubtful, so white should look for ways to sacrifice this stone to get free moves elsewhere. That is, white needs to treat this stone lightly, as aji in black's position.

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

Similar position, but white has too many stones to sacrifice (it's a pretty silly position, of course). It's a weak group that white has to tend to. It's urgent to make a running move to try and save this group right now this very instant.

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

White needs to make a move here to form a base. It's urgent. If black plays here, white has no base. Making a move on the other side, at around 'a', would be the wrong direction, because it forces black towards white's weak stone. Which might work if white plans to sacrifice that lone stone, but that's probably not a good idea here.

Click Here To Show Diagram Code: [go]$$W $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . X . 1 . . O . . . X . . . . | $$ | . . . a . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . |[/go]

Almost identical position, but white's stone and black's lone stone are in a different position. A move at 'a' is an inducing move: white gets to force black to force white to make a move white wants to play anyways (might not be the best move here, but it illustrates the idea).

Click Here To Show Diagram Code: [go]$$W $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . X . . 2 . O . . 3 . X . . . . | $$ | . . 1 . . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . |[/go]

Stronger players might quibble with these diagrams, but I hope that's at least partially useful.

OK, I'll quibble a bit.

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

Running at "a" is definitely better than at "b". However, running doesn't accomplish much else. One thought is to play at "c". Black may end up overconcentrated.

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

Yes, White can leave this stone alone early in the game.

Later, a play at "a" makes a small base.

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

A rule of thumb is one eye and access to the center. Where is White's eye?

Compare this with the case with one White stone. White has added three stones, but Black has added four. If Black takes another move to capture White's group, that is not a catastrophe. I could sacrifice this group. (OC, I wouldn't end up with it in the first place.

)

Click Here To Show Diagram Code: [go]$$W $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . X . 1 . . O . . . X . . . . | $$ | . . . , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . |[/go]

secures White's position while threatening to pincer the Black stone. In addition, Black's thickness in the top right corner is not now working well.

Click Here To Show Diagram Code: [go]$$W $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . X . a 2 . O . . 3 . X . . . . | $$ | . . 1 , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . |[/go]

White does not want to play :w3:

, as it approaches the Black strength in the top right corner. A play at "a" would be good, for the reasons given for the previous diagram. (OC, it would be less urgent.)

Click Here To Show Diagram Code: [go]$$W $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . a 3 X . . 2 . W . 6 . . X . . . . | $$ | . . 1 , 4 . . . . , . . . . . X . . . | $$ | . . . 5 . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . |[/go]

Not that

isn't better. But then :b2:

is not so good. (Better attach at "a", I think.) Even after :b6:

,

is working well, since Black is cramped on both sides.

Gochild's opening problems

Who is online