(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2] RU[Chinese]SZ[19]KM[7.50] C[Duan Rong 7p Using joseki in real games 4/130 Tianyuanweiqi 围棋 定式在实战中的应用 段嵘 29:40 mm:ss Translated by Daniel Hu UK 5d 胡怿伦 20190704 Welcome to the lesson. Today will continue discussing using joseki in real games. Let's look at the board. ] ;B[pq] ;W[po] ;B[pl] ;W[mp] ;B[oo]C[Last time, I discussed this joseki] ;W[on] ;B[no] ;W[pp] ;B[nq]C[The thinking and principles for each preceding move we have already discussed. ... So in previous weeks, we discussed and analysed the necessity of each move up to here. At this point white has 3 possible moves] (;W[qq]C[... That is why later this move was always played first] (;B[oq]C[... If white hanes first, black normally won't descend, but connect.] ;W[nn]C[... Normally in order to both protect the Q6 and also seize the R2 descend, white plays the press. ... Hence black cannot cut. After cutting, Q8 pretty much becomes a wasted stone after white pushes down and sacrifices, it turns into a position advantageous for white. Ok, we'll talk up to here. This joseki still has an abundance of variations. We'll wait till next week to discuss it. Thanks for watching! Goodbye!] (;B[mo]LB[pn:A][qr:B]C[At this point, white has a choice that depends on the ladder. This is because there are two vital points. One is that black can cut at Q6. The other is that the hane at R2 is very big ... Last week we discussed descending in combination with a real game.] (;W[qr]C[If white has the ladder, white can descend.]) (;W[rp]C[without the ladder, white must play the tiger's mouth.] ;B[qr] ;W[rr]C[Now if black hanes then white can black, maintaining a good deal of points in the corner]) (;W[qn]C[If you play over here, even though the shape is better towards this side] ;B[qr] ;W[rq]C[Simpy being haned by black means white loses a lot of eyespace and territory.]) (;AW[dd][cf][dp]AB[fc][kc][qd]C[In this board position. The white stones in the upper left give white the ladder so white can descend ... Hence if you don't have the ladder in this position you play the tiger's mouth. If you have the ladder you descend. These two choices have a certain necessity to them.] (;W[qr]C[Descending is rather more common in real games. So this joseki is chosen only when white has the ladder.] (;B[pn]C[Even without the ladder, black can cut] ;W[pm] ;B[qn] ;W[qm] ;B[ro]C[The kosumi is the tesuji] ;W[qo]C[The crude atari is a very practical move] ;B[rn] ;W[rm] ;B[rp]C[Black first extends liberties in sente] ;W[qp] ;B[om] (;W[rk]C[White must jump here. ] (;B[qk] ;W[rl]C[... Last week we also discussed that if black doesn't play a ladder breaker, or don't have a severe ladder breaker, then black can play to sacrifice the stones, and it isn't easy for white to handle. Or white has to be careful. ] (;AE[fc][cf] ;B[rq]C[Let's continue to look at sacrifice variations.] ;W[rr] ;B[sr] ;W[sn] ;B[sm] ;W[sl] ;B[rj]C[The throw in an hane shorts white liberties on this side] ;W[so] ;B[pr]C[black can block on this side. ... so we will continue from last week researching white's ways of fighting back. ... so let's look at white's countermoves. ... so if black wants to profit on both sides (S10 and Q2) and still seal white in, white has a good counter of the kosumi to offer to sacrifice the stones in return, and take the outside. This is rather advantageous technique.] (;W[sq] ;B[mm]C[If white captures, then we can say that black's sacrifice was fairly successful. ... This is black's hoped for position] ;W[nm]C[White can only push through] ;B[nl] ;W[ol] ;B[mn] ;W[om]C[White's capture doesn't reach 20 points and black's outside looks very good] ;B[fq] ;W[] ;B[qi]C[And later these poor stones are still useful for making territory on the right side] ;W[] ;B[ok]C[If white doesn't play, then black can seal white in. Black still have potential in this area. The poor stones can still be re-used. Even though black sacrifices, it isn't bad.]) (;W[ol]C[last week we said that white would very much like to cut here. ... so black can harass white on both sides like this and it's hard for white to get a satisfactory result.] ;B[nm]C[black must come out] ;W[mn] ;B[nl]C[black's turn here is a rather good move] (;W[sq]C[so white needs to capture black in the corner] (;B[ln]C[Black's atari is very active.] ;W[mm] ;B[lk]C[This knight's move is a good move. ... In summary, after black cut (Q6), black can actively offer up the cutting stones for white to capture, but it is still advantageous for black.] (;W[ml] ;B[nk] (;W[] ;B[mk]C[If white plays away and black reinforces, then black has all the sealing moves in sente. White only captured just over 10 points. White can't be satisfied.]) (;W[mk]C[By savagely pushing through you can get out, but it is only helping black settle the shape.] ;B[mj] ;W[nj] ;B[ok] ;W[lj] ;B[mi] ;W[ll] ;B[kk] ;W[kl] ;B[jl] ;W[jk] ;B[kj]C[Because white is low on liberties, white will feel very depressed.] ;W[km] (;B[il]C[Extend is possible]) (;B[li]C[Or capturing is also possible. Black has a lot of potential at the top, and can still exploit white's shape at the bottom. White isn't very satisfied.]))) (;W[lm]C[If white turns] (;B[km] ;W[kn] ;B[lo] ;W[kl] ;B[jm] ;W[ll] ;B[ok]C[Black can first take profit before capturing this stone. In the future, black can still exploit white's shape, around J9.] ;W[jl]C[If white still responds, it makes losing exchanges again.] ;B[im]C[From sacrificing, black gains profit on both sides] ;W[] ;B[fq] ;W[cn]C[Especially if black has already got the approach exchange. Even if black sacrifices, black can be satisfied.]) (;B[kn]C[black can also consider extending] ;W[km] ;B[jm]C[White gets out only painfully] ;W[kk]C[white can't attach] ;B[kl]C[white gets wedged]))) (;B[ok] ;W[ln]C[If black just captures, white raises his head. White can cleanly captured the corner and has extended liberties on the outside. Black can't be satisfied. White is very comfortable.])) (;W[ok]C[If white runs out, then black pushes all the way. ... In conclusion white can't pull this stone out anymore.] ;B[nk] ;W[oj] ;B[nj] ;W[oi]C[Even if black cannot capture with the ladder on any line] ;B[sq]C[Then this is still playable for black as black can short liberties from this side] ;W[sm] ;B[ql]C[self-injuring move, shorting white by an extra liberty, creating a situation where white can't short black's liberties] ;W[qj] ;B[ln] ;W[mm] ;B[op]C[Now white can't short black's liberties on either side.] ;W[pk] ;B[qs]C[Like this, black's two pressing moves where very profitable, while white just played almost useless dame points. Black can be satisfied.])) (;W[mm]C[White's good move is to counter-offer a sacrifice. The kosumi is a rather lively way to get out. ... So white just lets black capture, and it is a rather good counter.] (;B[ol] ;W[sq]C[If black still connects, when white captures, black can no longer seal white in. This is clearly a profit in sente for white.]) (;B[sq]C[When white kosumis, black can kill white] (;W[ss]C[white making a ko is a mistake] ;B[rs] ;W[qs] (;B[nl]C[black can protect the outside and now white is in trouble. [DH\] Leelazero says black has the advantage but this move is terrible with very low value since white will always win the ko [/DH\] Before, white just had to defend with one move to capture black unconditionally. ] ;W[ss]C[Now even after white defends with a move, it is still a ko. White is unwilling to let this happen.]) (;B[lm]C[[DH\] Leelazero's move])) (;W[sm] (;B[op] ;W[sp]C[directly shorting liberties, black dies]) (;B[ql]C[so black plays here to create a situation where white can't short black liberties] ;W[ol]C[After white captures, white still can't short black liberties, so black wins the capture race] ;B[op] ;W[qj]C[Although black captures white, but the loss on the outside is also very big] ;B[]C[Up to here, black had a profit of territory. Dead stones came back to life and captured white. The difference in accounting must be at least 30 points. But the price on the outside was too high. Once white cuts, white is very thick, and the amount of territory is not small either. This isn't profitable for black.] ;W[pk]C[later capturing the three stones is sente] ;B[qs]))) (;B[nm]C[If black doesn't want to lose so much on the outside, black can first atari. But this is a very loss making exchange.] ;W[mn] ;B[sq] (;W[sm] ;B[ql] ;W[ol] ;B[nl] ;W[ok]C[Even though black saves the cutting stones, it isn't really profitable] (;B[op] ;W[qj]C[Although white died, the capture is sente] ;B[] ;W[pk] ;B[qs]C[we can see it as this. Black's stones are stuck to white's thickness. White's stones have more liberties and are on the outside] ;W[] ;B[nk] ;W[lk]C[White can play from the open side. Black isn't very happy.]) (;B[qj]C[black can't connect] ;W[nk]C[this is a ladder [DH\] sometimes white has the original ladder, but not this ladder for example if black has approached at F17, in which case white can't play this an must cut at R10, allowing black to defend the P8 cut first. [/DH\]])) (;W[ss]C[[DH\] Leelazero thinks black's atari was a good move, but says white can now play the ko [/DH\]]))) (;W[nm]C[In comparison, if you atari, you still haven't managed to get out.] ;B[ol] ;W[sq]C[[DH\] This is leelazero's favourite variation for white. It says the corner is too big and this is a disaster for black. It says the kosumi is also good for white at 75%, but not as good as this at 89% [/DH\]] ;B[ml]C[Black still seals white in])) (;B[de]C[In this board position, the ladder breaker is very severe. ... White can't respond anymore and basically has two choices] (;W[nm] (;B[ce]C[Although black lost a lot being captured in the lower right, black gains a lot in the upper left. This position has been played by professionals.]) (;B[ol] ;W[nl] ;B[rq] ;W[rr] ;B[sr] ;W[sn] ;B[sm] ;W[sl] ;B[rj]C[the hane is still sente] ;W[so] (;B[nk]C[black can choose to surround the moyo]) (;B[ce]C[Or continue here. The P8 prevents white from capturing a stone, in sente. So even when black doesn't have the ladder, black can cut white, as long as there is a ladder breaker that leads to a relatively large profit, such as in this position. Then this is also playable for black.]))) (;W[ol]C[Or here]) (;W[ce] ;B[nm]C[white cannot block as black can ladder]))) (;B[sm] ;W[sl]C[If black hanes white can block.])) (;W[qk]C[If here, then black crawling and hane on the first line means white can't capture black which is serious trouble for white.])) (;B[de]C[Some players would ask what happens if black first plays the ladder breaker. After all, if black cuts first, black will die. ... So why doesn't black play the ladder breaker?] (;W[ce]C[If white blocks, then black cuts] ;B[pn] ;W[pm] ;B[qn] ;W[qm]C[If the same variation plays out, then black captures white's two cutting stones.]) (;W[mn]C[Black doesn't play the ladder breaker as white can first play this very crude move to defend the cut] (;B[lo] ;W[ee]C[white comes back to respond to the ladder breaker although white's press was loss making, black's ladder breaker was definitely also loss making. So overall, black didn't really profit.]) (;B[ce] ;W[lo]C[If black doesn't respond then white's block is really comfortable, sealing black in. Black's group feels depressed.]))) (;B[jp]C[In this shape, one other thing to watch out for is in case black has a stone around here. White has to be very careful and must not still play the descend move.] ;W[] ;B[pn] ;W[pm] ;B[qn] ;W[qm] ;B[ro] ;W[qo] ;B[rn] ;W[rm] ;B[rp] ;W[qp]C[I've seen this situation in amateur games] ;B[rq] ;W[rr] ;B[om] ;W[rk]C[I saw this in a game by two amateurs. So I'll take this time to remind everyone.] (;B[nm] ;W[mn]C[white thinks there's no problem as white can escape if black ataris. Black can't ladder.]) (;B[ml]C[but white overlooked this move. It's not just troublesome. White is close to losing this game.] (;W[nm]C[turning doesn't help] ;B[ol]C[White still can't get out. White has 3 liberties and black has 4 liberties.]) (;AE[jp]C[without that stone] ;W[mm]C[white relies on the kosumi to get out and escape. As black is about to be captured at P8, black has to return to the ladder situation] ;B[nm] ;W[mn]) (;W[mm]C[But when black has the extra stone] ;B[nm] ;W[mn] ;B[lm]C[Black seals white in from this direction] ;W[ln] ;B[kn] ;W[lo] ;B[lp] ;W[ko] ;B[jo]C[White is captured. White has to be very careful. When black has a stone here, white mustn't choose to descend.])))) (;W[mn]C[As go players, you might also ask why white doesn't first press then descend to avoid the ladder breaker?] ;B[lo] (;W[qr]C[... But after all white's press is pressing on the 5th line. We all know that pressing on the 4th line is already rather loss making. Pressing on the 5th line loses even more. For white to first lose out before black has made a ladder breaker. In that case black won't cut anymore, because white has already taken a loss. Black already has gains.] (;B[pn] ;W[pm] ;B[qn] ;W[qm] ;B[ro] ;W[qo] ;B[rn] ;W[rm] ;B[rp] ;W[qp] ;B[om] ;W[rk]C[If black cuts now, there's not much point as there is already no ladder. White's press defended against the ladder]) (;B[fq]C[Black can take sente]) (;B[qn]C[Later what white finds uncomfortable is this move] ;W[pn] ;B[rn] ;W[rp]C[If white defends, it is very painful] ;B[pi]C[Black can profit in sente. White's corner feels too small and the N6 push lost too much.])) (;W[pm])) (;W[pm]C[If you are unwilling to play the S4 tiger's mouth, another method is to first protect this cut] ;B[ql] ;W[qr]C[And then descend, in cases when you don't have the ladder. [DH\] leelazero says this loses 15% compared to S4 [/DH\] This is also not very good as black can take all the vital points in sente] ;B[ro] ;W[rp] ;B[qn] ;W[pn]C[In the future, once black blocks at Q2, not only is there not much territory in the corner, but white isn't yet completely alive. The Q7 tiger's mouth bump is too big a minus.]) (;W[rp]C[Probably over the last few years, the feeling is that white isn't too satisfied with the tiger's mouth]))) (;B[pn]C[Does white fear black directly cutting? This is truly in question.] (;W[pm]C[White must wedge through.] ;B[qn] ;W[qm] ;B[ro]C[The kosumi is still the vital point] (;W[qo]C[White clearly can no longer atari this side when white is missing a stone] ;B[rn] ;W[rm] ;B[rp] ;W[qp]C[White's corner dies. This is definitely unacceptable.]) (;W[rp]C[White should tiger's mouth bump.] ;B[rm] ;W[ql] ;B[rl] ;W[qk]C[Black can only crawl on the second line. Up to here, black still has to crawl or else he doesn't have enough liberties.] ;B[rk] (;W[qj]C[White can extend] (;B[pr]C[Black now has many liberties. He can spend a move reducing white's eyespace.] ;W[mo]C[White ] (;B[rr]C[Black still hasn't captured the corner cleanly, so adds another move.] ;W[mq]C[White blocks. Although black captured a corner, white completed an influence, sealing black in. There is a lot of thickness and potential. ... Even if black captures, it's not profitable, it's a minus.] ;B[] ;W[rj]C[And when white turns here, black still has to short liberties to capture.]) (;B[lr]C[Even if black can play the knight's move, depending on the global situation, ] ;W[rj]C[If white has potential here, white can turn.])) (;B[] ;W[rr]C[Because if black doesn't play then white can live unconditionally.] (;B[pr] ;W[sq]) (;B[sq] ;W[pr]))) (;W[mo]C[Or first stick. ... If the value of the upper right side is small, first block.] (;B[lr]C[If black comes out, white can live in the corner. If black defends the lower side group, white can extend R10. If black hanes R10, white can attack the lower side. Black also feels like he is crawling too much on the 2nd line.]) (;B[pr]C[If black chooses to capture the corner.] ;W[mq]C[white can block in sente] ;B[rr] ;W[qj]C[And extend. This diagram is completely satisfactory for white.])))) (;W[qn]C[This is absolutely impossible] ;B[pm]C[Letting white's two stone become isolated on the outside.]))) (;B[pr]C[If black still descends] ;W[qn]C[White defends directly as the O6 press exchange is bad and a classic crude move that damages the N4 stone.])) (;W[op] ;B[np]) (;W[nn]C[Originally, the order of pressing and hane didn't matter. ] ;B[mo] ;W[qq] (;B[oq]C[Either would lead to this result.]) (;B[pr]C[Afterwards, perhaps some players wanted some variation. This choice appeared. The O6 press is already loss making.] (;W[rp]C[If white plays the tiger's mouth. Black's descent is threatening white's territory and eyespace with S2.]) (;W[qn]C[If this tiger's mouth] ;B[qr]C[Black turns inside. If white presses at O6 first, it may give black this extra choice. If black on the lower side doesn't fear white blocking at N3 much, then black can choose this variation.]))))