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HolIgor: This continuation could be chosen at . I did not like white's thickness.
Herman: So how about this? If at a then at b. c is sente for white (also for black, but then black hurts the stone at for relatively little gain.
fractic: Now that play has gone on I would like to give my thoughs on . I think it's in the wrong direction. I think puts white on the spot. Sure is one space too far but White now faces a dilemma. Playing a is prudent to prevent Black pressing on b but then black gets to form a perfect moyo with a move around c. If white doesn't play a to play the wedge at c black could force from the top and then come back to play b ruining white's moyo and putting at a proper distance.
Andy: For this reason, white could tenuki with to play the wedge. Black can confine white to the corner in the bottom left, but by playing 3-3 in the first place, white never really intended to make a lot of development here anyway. If this corner reverts to the standard 33 Point Invasion, white is comforted that the effectiveness of black's center influence is significantly dampened by the high stone.
Tapir: Is it necessary that this follow up is played after stretching instead of jumping? E.g. if white pushes once more and black answers and white plays at then. For people who know joseki this may be a joseki choice question, I'm quite weak at it, but I can't believe that white would allow black to play , I'd rather play an inferior line but I won't allow this. However I believe Black should never tenuki after (), there is still aji but... I don't like this result.
fractic: If here instead then white can tenuki with . If White would continue locally with a Black would surely tenuki to play around . Black is again left with the move at b but this is a bit further away from whites moyo than in the previous diagram and is in the perfect place to ruin Black's prospects at the bottom.
fractic: I suppose it is a bit wishful thinking. But I wouldn't mind the sequence shown below. But here is definatly good. By the way, I haven't seen you make a move yet. Why not join the game?
fractic: To Andy: If White is going to tenuki at some point than why not play as in the alternative. Black is very unlikely to tenuk with and because of . I'd say develop the corner as much as possible before playing tenuki.
Andy: Well, I'm not sure. If I were black, I'd tenuki with in the alternative diagram because makes look a little strange.
fractic: If Black tenukis with one space left of that is an excellent attack for white. It also helps limit Black's moyo.
fractic: I agree that it's playable for both. I suppose it's a matter of style.
MrTenuki: If Black plays as in the diagram, shouldn't White immediately invade the moyo at a or b instead of playing as shown?
Tapir: Is this joseki? Any explanations on SL about this move? Never seen before and would never occur to me.
Tapir: Ok. I shall study joseki... :D
Holigor: This is a move into uncharted territories. The search in the gobase.org revealed that in the pro games black always captured.
tapir: Sorry, i'm not pro. If I see the foreseeable result now, i suppose this thickness is too good for white. Else white would have an eyeless running group instead of a ponnuki. Blame me, if we lose.
Holigor: this is not about blame or winning. A discussion needed to keep the lesson.
tapir: Sure. I dislike now. But at first I thought the thickness facing the left would be more valuable. (We may move this to discussions...)
Herman: See: Probe - Popular Misconceptions for analysis of this position...
tapir: There's nothing about . Basically it says , secures the corner and may be heavy and comply with white's wish to establish a group in the framework... but white's group is not weak anymore after etc.
Herman: Yes. So is a bit slack, professional prefer the sharper line. should capture, especially in this position, as after , the ladder works for white. Had the ladder not worked, then should probably capture immediately, which may lead to a complicated ko if black plays at . I think the end result is reasonably good for white, but is by no means a disaster for black.
kb: Herman, I don't agree. The sharper line isn't good here, because it's too easy for White to create a solid group in the center of Black's formation. I think Black's original hane is not good. Pulling back at is better. The adage "extend if you are strong" helps here a lot.
Herman: Yes, I agree. The sharper line is wrong here because the ladder is bad.
kb: In fact, White's probe is also a little suspect - White should reduce at a instead. (I can add diagrams if my words are unclear.)
fractic: I'll add my reasons for not really wanting to play . I expected Black to just capture right away. The ladder at a does work but after Black b capturing still doesn't secure an eye. So I felt the white group would get a bit heavy. I'm quite satisfied with the way the game continued.
kb: Like Kageyama says, if you get a chance to ladder a stone like that, just capture it immediately and let your opponent play two moves in a row wherever they like ;) It's a solid White group in the center of Black's sphere influence. That result would have certainly been better than the game is currently. Black still has an opportunity here.
tapir: there ll never be too much tewari analyses on sl. so please show. i m interested to see which move is looking bad in it.
is the right answer to . It looks to me like / is helpful for White, and is forcing without the exchange. looks slack. -JoelR
tapir: Shouldn't we analyse the whole sequence - to the same board situation? Because now offers black a gift before capturing with . Analysing should be done with the whole sequence. Reordering half the sequence and omitting the moves which are bad for one side... isn't tewari in my humble kyuish opinion.
Herman: is ok in this situation, I think. It is basically a small endgame move, but because black can play it for free now (white will certainly respond now), but maybe not later (if white is fully alive later in the game, she can ignore this move) it is playable (though black might also save it for a ko threat). I think that the suspect move is ( in the original diagram), so how about the following tewari:
Here, looks suspect, pushing from behind. and are both bad moves, both give away a stone needlessly while strengthening the opponent, and they cancel out.
tapir: Isn't the point of tewari to make one side look natural and the other bad - without a necessity to quantify the badness. With both sides playing bad moves you can well question "that both bad moves cancel out" - maybe one is more bad than the other? (E.g. if you change and here, you still have looking suspect, looking even more suspect and two outright pointless sacrifices. But such manipulating of the number of bad moves doesn't show anything. One side need to be correct as I understand tewari.)
MrTenuki: Here's my try.
Here, blocks the inside, White moves out with , and Black's double hane at , while seemingly severe, actually gives White the chance to play as a forcing move. (This forces .) Instead of defending at or playing the second atari at a, however, White plays to threaten to capture in a ladder. Black then plays to capture one stone while temporarily abandoning , and White tries to forces Black to take the initial probe off the board with . Black then suddenly realizes the mistake and finally defends with , and White, given the miai of capturing or , chooses the second option with .
Problem: White is still not playing ideally with this sequence.
kb: No problem. Black started with 2 more stones locally, so nothing White does can be ideal (in terms of getting an "equal" result).
kb: I think you guys need to look at this differently. In the West our attitude is always "They didn't play joseki! How can I punish it!" Have you considered that Black's result could be OK? Of course, it could be better, but if you were Black are you really that dissatisfied? White's group is low and still isn't alive. The only bad exchange in my opinion is -. Of course it's necessary for White to play some forcing moves that look "bad" (-?) but then you're just lying with tewari. Don't forget Black also gets sente here, which is very important.
"Enclosure Josekis" is an excellent book for this type of thing. I think we will learn more from continuing the game than the discussion, so you can actually see and feel what, if anything, White's quantifiable advantage is.
HolIgor: Black might have chosen to enter the top over defending the corner. This is one of the variations. One would expect the top becoming small.Black would eye reducing the left side.
Joelr: I agree. I looked at Black 29 at a, a pivot point between the two sides. But it doesn't reduce the top much. Why the / exchange? Doesn't it strengthen White more than it makes them heavy?
HolIgor: There are pros and contras, of course. But the exchange pevents the slide in the corner, so I would play it.
Andy: was mine, but I'm not too thrilled with how it turned out. The idea was to expand/consolidate on the left while poking another stick into black's points balloon in the center. White has to eventually connect in bad shape at a, which is painful. I was looking to prevent a black move at b which would shrink white's left while securing the center, but seems crude. Are there better alternatives for white at this juncture?
Joelr: I was surprised by . I thought / was enough to settle the top, at least to the point that the bottom left and bottom right were more important. I have been worried about White c for some time, and would have played at d, inducing e, before coming to b. So after , I think White c does more to run amok in Black's moyo. I recognize I've advocated not settling for both sides - am I too sanguine?
ThorAvaTahr: I would like to speak up for . IMO not reinforcing this group equals not being able to build up any kind of moyo like black has now. White could easily attack the group while building up strength in the center.
tapir: looks like a focal (?) point somehow, but it helps black in moyo-building. Compared with Black at b it gains how much? 10 points maybe? I would try f or c as White. I don't think an exchange which reduces white to one eye but let her run straight into the black zone of influence is good for black. That's why i played d as black. (After c, d, connect, e white has forcing moves from the outside and isn't in big trouble imo, similarly she is settled already on the left.)
MrTenuki: Considering what had happened by the time that Black played , would it be a good idea for White to play around g?
HolIgor: For me the region of was not urgent. White does not have to answer b. Both white groups on the left are quite alive. Connecting them is a lot of points but, points, that's yose. Black strengthened with yet that eyeless group is still the most important at the moment. It should be attacked from far. That would help white to build an alive group in the center. After that white might be able to play in the region of h or i. It is not easy to choose the point of white's attack at 52nd move but something around tengen would do. On the other hand is a lot of points and there is still a fight in the center. Winning that fight white wins the game.
fractic: This looks likely.
tapir: Adding , and at one a this looks good for black, imo.
Andy: White cannot play this way. White will crosscut with for sure.
fractic: I don't really see any satisfactory continuations after the crosscut either. White is in for a hard fight no matter what it seems.
kb: should be here to gain access to the center. In the real game, Black will get a lot more.
JoelR: What if Black directs White south, where Black has more strength? Also, what if Black pursues the ladder?
tapir: Without counting pointwise it looks like only the lower and upper right together equal the prospective white territories on the left and upper edge. The upper edge is still open, as is the left part of the lower edge. Black has further prospects in the center and lower left (not counted yet) much bigger than Komi + approximately 8-10 point territory for the two small groups. Can black start playing secure and endgame now?
HolIgor: Perhaps you're right, but it's rengo, so the moves are not discussed before they are made.
tapir: After White 86 would have been better, I suppose? It is not wrong to do a bit positional judgement, even posthumously.
MrTenuki: In the actual game, was played. However, it seems to me that could be cut off afterward, which means a swing of more than 10 points in Black's favor. Does the White team still have a chance, and should be played differently? For that matter, should White take a chance with the center group and defend the top as early as ?
Andy: It looked to me like black could reduce white to one eye in the center starting with a placement at a if white played tenuki at . Of course, I could be wrong about that. :)
MrTenuki: I don't like the tenuki... surely responding to is bigger? (If Black gets to play at , the worst thing that could happen is a small reduction. White's center group, on the other hand, could be in danger if Black gets two moves in the area...)
JoelR: I also think is a very small move. Is there a mechanism for undoing it?
Anon: I think it's called begging... :-p
tapir: I agree to B103. But I want to bring to everyone's notice that black leads comfortably in the count of empty triangles :)
Andy: That's why white is catching up in points. :)
JG: Possibly would have been more interesting for than the move played (immediately to the left). A play at gives more space for eyes and better chances to fight back if Black tries too hard to kill. Of course, I do not actually understand the starting position.
tapir: 111 and 113 don't work together. Giving the lower left edge in sente while saving the lower right to turn to other big points looks better for black.
unkx80: Actually with the and exchange, this works. If could be at instead, then this would not happen.
tapir: Anyone to explore this any further? I don't see what white can do after this.
Herman: The - exchange had already happened before the atari of . After , the black stones are captured and white is alive. If does not work (eg because black played at ), then white can try the atari from the other side ( at ) and will probably live as well.
Celebrir: What about this variation ? Better for B ?
Andy: This kind of thing is why I made the forcing move. That way white can capture and have miai for a second eye on either side. I thought that black would allow to connect out to the left while killing the other white stones, which I thought was sufficient for white to win the game.
Unfortunately, I had at and didn't notice that the squeeze kills the white stones.
Kanzenryu: I'm not good enough to suggest any moves, so I'll just post this http://img144.imageshack.us/img144/2562/ongoinggame6move120.png
JoelR: I would have ignored W112 to stop the bleeding. White made excellent use of the interplay between the invasion stone and the white center group. Andy, is this what you meant by suboptimal move order? That White should try before to see what the response is?
Maybe this is alive, but looks like a tsumego problem :)
unkx80: What are the prospects of killing if is played at a? I don't have the answer yet... ;)
Herman: Here's one sequence. Looks more problematic than I thought :-)
Herman: So black should play this , after which white can go all out and start a semeai... (though perhaps should be at a to prevent trouble on that side? tricky... (-: )
MrTenuki: Shown above is the actual continuation in the game. Are a and miai for life?
unkx80: Should be this W122...
symplicity: To open up another line, how about B119 here?
Herman: I think this has more chance of killing white than B119 in the game.
MrTenuki: Batavia? called a "small gote move." Judging from the smiley face after the comment (Tapir-- thanks for reminding me that), though, I wonder whether the comment was meant to be a joke-- is the follow-up at a enough to call gote no sente?
Batavia: i do think was big enough to play. if it's the best move i don't know but i felt that black playing at certainly would have been big. now w has some nice followups. to reduce the lower right. for black to answer at a is way too passive at this point. therefore, in hindsight, was maybe a little early and i should have looked for some moves that were really sente.
tapir: I initially thought about t here. But it ends in connect and die.
MrTenuki: (continued from previous comment) (The - exchange is at least sente.)
Tapir: Since this area is still unplayed, it is too early to comment on follow-ups in my humble opinion.
Batavia: you can't discuss moves if you can't discuss their followup though.
Tapir: Well, i believe it is too early to discuss W126 yet.
Herman: I can say that I generally refrain from discussing moves like this, where the follow-ups are still possible, because I might give other players good ideas :)
Tapir: You play white... and most probably any possible idea here would be a white one. But black should know them, so please share :)
Herman: Well, if white plays directly at b, the entire lower right black group is almost certainly going to die. So black definitely needs a defensive move here. In fact, black should probably play here right now! (If you are on the black team, please do not read the preceding comment, or try to forget it if you already have read it)
Herman: I think that in fact, in the previous diagram is a mistake in the order of moves. White should play like this. If White cuts with w28, the forces white to live in gote in the center, after which is sente against white's group on the right.
If white instead defends with at , black can than play the - exchange from the previous diagram, and he will have gained in the exchange, because the cut at in this diagram is smaller than the hane in the same place without the stone at (because the response at a is now sente instead of gote.
If white defends with taking at , then black can take sente and play elsewhere, because the cut in the lower right (at ) is now even smaller, with black having the ko as an option.
Malcolm This looks more effective to me than the move played in the game. I can't see how Black can save the marked stones - but there are lots of possibilities, I haven't read it all out. Anyway, this move 'feels' good!
Herman: I see very few options for black her but to defend at a. For my intention in the game, see next diagram.
Herman: My intention was this sequence, after which black cannot avoid either the cut at a or the connection at b, also effectively cutting. I played here, rather than at , because it seemed there was less scope for variation. and the - and - exchanges seem interchangeable. Black does have a better alternative, however, with at . White can then connect at , and after black connects play c to capture the stones. Big endgame, but not a knock-out punch :)
Malcolm: Thanks for the analysis. I'll try to find time to read it out. I changed this diagram as I think only two stones should be marked , if I follow what you're saying.
Malcolm: After 3, if Black plays 'a' or 'b' White plays 'c', and if Black plays 'c', White plays at 'a'. This looks to me like game over for Black...
tapir: Black a, White c, Black d, now white can't cut. Otherwise his three stones around c will be captured with Black b next.
tapir: Well, it is too late, i don't even recognize atari :( ( at b should transpose to one of the noncut-lines discussed above.)
Malcolm: I don't think so, tapir. See the next diagram.
Anon: If black ataris first, W can no longer cut at 'a'. If W cuts at b, B can capture and starting at c.
Malcolm: I think after 4 W can cut at a. There are then many variations, but I haven't seen any where B saves the stones...
tapir: can't capture directly, otherwise Black at c takes two stones and connects. one line above ends in another connect and die.
unkx80: It seems to me that the - exchange can be omitted.
Malcolm: White can salvage a ko. Still, maybe this is not such a good result... :).
Batavia?: It's quite easy, if White needs the points to win then it's a good thing to do. otherwise White just risks some stones himself. But since the burden on Black is heavier than the burden on White I think this ko tends to favor White. Then again I haven't counted the ko threats.
Malcolm: OK, I was blind. The conclusion is that the alternative move I suggested for White 140 is not as good as the move in the game. Thanks people for the help!
MrTenuki: Is it only me, or should be played at a since the threat to capture 4 stones should be sente? Plus, I wonder if reverses because Black can ignore and start the sente sequence a-b-c-d (which would render the monkey jump meaningless).
Batavia: It's always just a matter of carefull counting which move is bigger, and the risk of playing with multiple people increases the risk of error.
Herman: Here is a rough estimate of the score after move 158.
White score (/):
Top: 16 points Left: 31 points Bottom: 5 points Right: 7 points Prisoners: 4 points Komi: 6.5 points Total 69.5 points
Black score (/):
Top right: 46 points Center: 11 points Bottom right: 8 points Total: 65 points
So white is slightly ahead, but it is Black's turn to move...
Exciting game :)
tapir: Would it have been better to play the big reverse sente at W156 instead of B155?
Herman: Yes, I think so, but white could (and should) have played W156 before switching to W154, so in the end, the result is the same.
Hylebos: Couldn't white have started a massive ko to cut off the black group if he captured at Six instead of peeping at the square point like he did in the actual game? Am I missing something big?
fractic: With the sequence on the left Black can live in the corner and make a and b miai to save most of the stones in the center. White can still capture at the expense of some of her own stones.
This is part of the reason why I played . Besides preventing Black's sente monkey jump, it reduces the room for Black to make eyes. I envisioned black would immediatly save since White capturing there is going to be unpleasant for black and then the b-a exchange would also be sente for White. Perhaps I should have captured right away.
fractic: I read out this sequence. Which gives about the same result as above. White can still play at giving the same result too. But if played like this Black might do something drastic since he's behind and play a monkey jump instead of . Of course this gives White the ability to play a ko for the life of the group. But if Black wins White's territory is gone.
W166 should obviously just have captured the stone. Black has to defend against the ko and White can then reduce the center.
Herman: Some comments on the endgame here:
(@ ) was a good move, defending the corner and threatening ko. After , for both black and white the stone is key. If white captures it, they threaten to cut off the corner in ko, and at the same time prevent the lower white group from ever becoming seki (as long as isn't an eye, black can make a gote seki with b.
So I think best play is for black to defend with at , forcing white to connect at a. after which black needs a move at c to prevent white from rescuing the stones in the center.
Apart from the center, however, is the biggest move on the board, taking points in the corner while threatening a monkey jump. The other big move left is d, with which white can connect in the corner and make 6-7 points in gote. and are white's privilege, and are urgent. If white plays d directly for the points in the corner, black can play reverse sente at e, which is very big.
I think that on these ten moves, black has probably lost about 3 points, mainly because of the failure to defend . The score estimate below shows that the score on the board is roughly even after . White leads by the komi and has sente. It will be hard for black to come back.
White score (/):
Top: 15 points Left: 32 points Bottom: 8 points Right: 7 points Prisoners: 5 points Komi: 6.5 points Total 73.5 points
Black score (/):
Top right: 46 points Center: 11 points Bottom right: 8 points Bottom left: 2 points Total: 67 points
tapir: White gained at w, lost at b, Black has sente. So it is closer than 10 moves ago, or the count is simply different.
Herman: Yes, black has gotten closer. Move 173 by ThorAvaTahr was a good move, white should have already played that, as it was sente, so black gained some points there. Assigning the b marked point on the left as white territory was a mistake on my part, and if the sequence you posted above had been played, black would have gained some more points there.
Andy: I didn't understand this ... is there an advantage here over the solid connection at a? Connecting solidly seems to reduce the aji in this position without costing anything.
Herman: No, no advantage, should have been at a. This one leaves the aji of the peep at b.
JG: I wanted to play at , expecting Black to connect one point below, and only then Wa. But the yose was being played too quickly...
tapir: Isn't Black happy to take 2 stones and to live big inside former territory then? I would be.
Batavia?: the reason i played 72 is because otherwise black had another push at c later. Of course this is gote and very small but i just didn't think about the peep at b. Not saying it's good just giving you the reasoning
ThorAvatahr: I had something different in mind for
ThorAvaTahr: I don't expect to kill white, but if he has to capture the black stones it will surely cost him points (what's the name of such tactic again?)
Herman: semedori. But shouldn't white play at ?
Tapir: I apologize - the last two sente moves not considering the original intentions may have given the game away. My intention was to play all the sente sequences available, finishing with the then only big gote play after which black would have been slightly ahead according to my count. But white gained at least three points on the left now and I doubt black will have enough. Just: How big is the semedori, is it sente?
ThorAvaTahr: Thx; Well that looks more dangerous for white, what do you mean exactly? I would rather expect white to play at .
Tapir: Gote, isn't it?
Herman: Like this (after for as move 179 and 180)
Herman: Now, it is semedori. White captures 9 stones, for 18 points, plus one at a, but has sacrificed 3, so gets 16 points here, which is more than in the game
ThorAvaTahr: hmm, you don't count the outside, black get's some sente points there, but clearly not enough... how about just extend then, I can't believe that white can safely eat all my stones.
(Posted by tapir)
Herman: Yes, better than the game. In this diagram, white's lead has shrunk to less than 2 points, I think.
Dieter: When ThorAvatar? announced his reverse sente move of 227 but forgot to put it down, I was hoping for a certain move that removes aji and therefore gains points, but which was not reverse sente. I couldn't find a reverse sente move. When it got played, I still didn't think it's reverse sente, but mere gote. I'll reveal the move I preferred later.
ThorAvaTahr: Hmm, I see... I think you are right, the actual value of move 227 is slightly less than 1 point.
Tapir: We are lost, aren't we?