Hal9666: I just lost a game, by 105.5 points, because I lost a very important group. I would have resigned, but I already lost and won a game by resignation today and I didn't want a third to end that way. Could I have saved this group?
Note: White circle is move 11. I was black, the group in question in marked with a square.
TheBigH: My reading ability is not great, but it seems to me that trying to capture the white stone between and was a mistake. You deprived your marked black group of the liberty that was at and, as you see, you could not capture the white stone. Maybe one space lower could have allowed you to escape downwards, but I think next to it still captures your group in a Net.
tapir: Like this nobody can tell, as this depends on the ladders, the net doesn't work as White has only two liberties.
Hal: I didn't post a larger diagram because there were no unshown friendly stones in any spot that would help. All of my stones at that point were to the right or upper left.
Tapir: But even this result is not bad for White. Compare with the simple defense against the cut below.
Slarty: I wish you had provided a diagram at the moment of your question. Without that, it is unclear.
tapir: In this situation my main message would be that saving these stones is unimportant. They don't cut anything. As opposed to saving the three stones a matters because it prevents being cut off.
Hal: I was trying to prevent White from walling off the center(with ), but I was also trying to protect the top. The group was supposed to gain center influence, which is why it's important. It became more important when it cut the three white groups with move 4 in my first diagram. It may not accomplish it's goals well, which would mean that I picked the wrong part of the game as my failing point.sp
Slarty: Whatever the original intent, it is plain to see at this moment that the three are unimportant. They do not affect the life of the surrounding white stones. is important, and reducing white's potentially huge center is important. If they are not clear though, there's no reason to throw this many words around.
tapir: Exactly, though "it is plain to see" probably doesn't help much, when you don't yet see because you are a beginner. I would say: As beginner one usually is too attached to each of your stones. Try to sacrifice stones even if you can save them, if your opponent sacrifices too, try to sacrifice more. Not only is this highly educational but it will win you many games outright because people tend to spend too many moves on capturing.
Dieter: To know if the stones can be saved, we need to know the full board to see how the ladders work out. To know if they're worth saving and if your goals would better be accomplished otherwise, we need the full board too.
Hal: I've actually already read those pages, but I often forget that stuff when actually playing.
Hal: I thought a smaller diagram would be better, but I guess I need a full one. Please only comment on the marked group though, I am aware I made several other mistakes mostly in the opening.
Below is a diagram that was based on the above diagram when it had a missing stone. To Slarty, I didn't know if you would want to modify or just delete the following, so I'm leaving the choice to you.
Slarty: OK, the marked stones are important because the adjacent white group would live by capturing them. You could pull them out and fence in the white group with moves like a. The giant black group is alive, hence connecting at b is not very important. White is not directly threatening to kill the three stones. Taking the next opening move (c for example) would not be wrong.
Dieter: So let's look at this position. White has just played . Hal is Black and wants to know what to do now. This is how I interpret this BQM.
Unlike Slarty I see the central chain of three black stones as disposable, since they are not cutting stones. White is already connected and spreads its arms around those stones. So, saving these stones will only deny eyespace to White. I think this puts a heavy weight on Black and it's not necessary to kill this group to win the game. That's why I would treat them as disposable.
- Shapewise, a comes to mind for central influence.
- b is an obvious way to take some more territory but it is too close to Black's strong group.
- c strengthens the corner while keeping an eye on White's bad aji
If Black decides not to harass that group but play away from this position altogether, then all of the circled points are conceivable big points.
tapir: Just for the record I would still play b without hesitating a second. It keeps the connection. You can avoid defending with your next move (after White connects) with the corner being so close, but playing b pretty much looks like the obvious move here.
Hal: Thanks for the help everyone. I think my question is answered, along with questions that I should have asked instead. This has taught me a thing or two about go, and making BQMs, that I will hopefully keep in mind in the future.
ThorAvaTahr @ tapir: to me 'c' is a clear refutation of 'b'. 'c' is making more territory and strenghtens the corner. After 'c' both sides are alive, that is why connection is not important here. In fact as Dieter said, it is quite conceivable to treat 'c' and 'b' as miai and just take one of the remaining big points. (in fact 'b' doesn't even look like the best point locally, i would prefer 'd' for connection, see BQM569/preferedconnection)
tapir: In fact, I agree with d being better for the connection, though not with the reasoning in its favour :) See subpage.