(;CA[shift_jis]FF[4]RU[Chinese]MU[1]MU[0]AP[SmartGo:3.1.4]SZ[19]GM[1]EV[AlphaGo selfplay]
RO[20]PB[AlphaGo]PW[AlphaGo]KM[7.5]RE[B+R]MULTIGOGM[0]
;B[pd];W[dd];B[qp];W[dq]LB[oq:A][co:B][do:C][nq:D][cc:E]C[This board position brings to mind an example of how AlphaGo is influencing human pros. Before AG, the tight shimari at A was Black's most popular move, while B or C were also commonly played moves. All three of these moves have lost popularity in the changes that came with our study of AG. In the Master series against human pros, AG liked the big shimari at D. In this self-played series AG could play at B or C, so it seems to be different from the AGMaster we saw playing against humans. So, in the year 2018, most pros now like to play the AGMaster move at D, with B or C less popular than before, but still being played. The tight shimari at A has all but disappeared. AGZero actually played at E once, and both D and E are shown in the AlphaGo Teaching Tool as moves that AG likes in this position, but I think most human pros are not quite ready to play at E yet. ]
;B[co]LB[np:A]C[In my comments at move 4, I did not mention the other move that has become popular for Black 5 in human play during the year 2018, which is the big shimari at A. This is interesting, because it is not an AG favorite in this exact board position, but AG plays it in similar positions. Maybe this is an example of the flexibility of humans, as we play around with the ideas given to us by AlphaGo, trying to find something new. ]
;W[oq]
(;B[pq]C[Again, AlphaGo has changed how we play. This board position can be found in the AlphaGo Teaching Tool, where Black's kick at 7 is shown to be AG's favorite move, and this move is gaining popularity among human pros now. Before AG, a pincer on the lower side was played most of the time (see var). ]
;W[op];B[pn];W[lp];B[ep]LB[pq:A]C[The sequence from Black A sets up this pressing move. Black A grabbed some extra territory in the corner, the tradeoff being that White now has a strong position on the right part of the lower side. By pressing from above with 11 and inducing White to crawl, Black will give White a solid but low position towards the lower side while Black makes influence towards the left side. Both of these corner sequences can be called even locally, but in combining them Black is attempting to create an efficient shape. The logic behind this is that White will have two strong positions right next to each other on the lower side, and this might be seen as an overconcentrated shape for White. ]
;W[eq];B[fp];W[gq]TR[lp][op]LB[qk:A][qo:B]C[Logic might suggest that Black's plan has succeeded (see my comment at 11), and that White's marked strong group is redundantly reinforced by White's strong but low group to the left to create an overconcentrated position and give Black an overall advantage. However, Black also has some problems that make this position about even. Black has yet to make any specific use of the wall on the left, and when it is not connected to a moyo, the wall could potentially become a weak group. Also, the LR corner position is not finished. Black must add a stone at A to cash in on the local advantage in this corner, and without that stone White has a potential attack at B. Black doesn't even try to solve any of the above mentioned problems, so we get to see them all come into play in the game variation. ]
(;B[cc]C[In a distinctive AlphaGo style, Black invades at the 3-3 point. Pushing on the lower side is also an important point (see var). ]
;W[dc];B[cd];W[cf];B[ce];W[de];B[bf];W[gp]C[White could have continued in the UL corner, but instead takes this big point, which is a feasible way for White to play.]
(;B[cg]C[This atari is one way for Black to punish White for playing away, and Black will take a local advantage in this corner. Otherwise, Black could have cut (see var). ]
;W[df];B[cb];W[gn];B[hd]C[Black's pincer is in the typical AG style, coming very close to the White wall. Black is refusing to give White space for eyes, and Black has potential to attack this White group, ]
;W[qo]
(;B[po]C[Pushing through here is Black's strongest move. If Black want to avoid this fight, it is also feasible to cover on the 3rd line, but I like that for White (see var). ]
;W[pp];B[qq];W[qn];B[or];W[nr];B[qm];W[rm];B[ql]
(;W[rl]TR[qo]C[This fight starting with White's marked move has been seen in high-level games for centuries, and there are a number of examples from games played in the golden era of Japanese Go. This might be an unusual case of our accumulated knowledge being better than AG's ability to calculate the position, because crawling on the second line (the game move) will lead to a bad result for White. With this move White could have cut on the 4th line, which I am calling the correct variation, or a hane on the 2nd line is also a common move, but that is bad in this board position. I have added the two variations. ]
;B[rp]LB[rp:A]C[Black A is a vital point that takes away White's eyespace and expands Black's space in the corner, thus making it relatively difficult for White to win the ultimate semeai. ]
;W[ro];B[so];W[rn];B[qk];W[rk];B[qj];W[rj];B[qi];W[pr]LB[ri:A]C[Cutting on the second line takes away Black's eyes and sets up a semeai. Crawling at A was another option, but I will not go into that as in the end it is just another bad result for White. ]
;B[qr];W[os];B[ri]
(;W[rs]C[White's placement on the 1-2 point is the tesuji here, while an attachment at the 2-2 point would be a mistake (see var). ]
(;B[nc]C[Black plays away, but can still make a seki in the corner, as the variation shows. It is just not big enough to play immediately. In the overall position, Black is ahead. ]
;W[hf];B[if];W[ig];B[jf];W[hg];B[jg];W[qc];B[qd];W[rd];B[re];W[he];B[id];W[jh];B[kh]
;W[ie];B[je];W[ki];B[ji];W[ih];B[lh];W[jd]TR[hd][je][if]C[This cut will not accomplish much immediately, but it reduces the liberties of all the marked Black stones, and eventually will help force Black to play an extra move to capture White. While I would assume that AG has it calculated, a strong human player would just cut, with experience indicating that it will not be wasted, but not necessarily having read out all of the variations. ]
;B[gd];W[jc];B[ib]TR[jc]LB[eb:A][rb:B]C[Black has a potential connection with A, and it seems unlikely that Black will have any serious trouble here. White has forcing moves in the vicinity of A that will be useful as an endgame sequence much later in the game, and meanwhile the marked stones can cause trouble in connection to the aji at B. White will start by forcing from the center. ]
;W[li];B[mh];W[mi];B[nh];W[ni];B[jj];W[hj];B[dg];W[eg];B[eh];W[ff];B[kd]LB[kd:A]
C[Black establishes the whole area as territory by playing at A. ];W[ml];B[fm]TR[jc]
[ji]C[Similar to the marked White stones, the marked Black stones are a example of a gambit-like sacrifice with which Black is going to attempt to gain forcing moves from both the left and right sides. ]
;W[gm];B[fk];W[gl];B[nn]LB[pm:A]C[While reducing White's area in the center, this move gets rid of the cut at A, and this links up to the potential seki in the LR corner. ]
;W[mn];B[rr];W[sq];B[qs];W[sp];B[no]LB[rr:A][no:B][mq:C]C[Black plays at A in the corner, looking like Black is trying to set up a seki, but actually the meaning changes when Black plays at B. The threat of Black C can be used to change the corner fight into a advantageous ko for Black, and later in the game I will be showing even more sinister variations as the whole area erupts into a chaotic fight. ]
;W[ol];B[om]
(;W[dl]C[White plays this invasion on the left side at a time when White's lower side area looks a bit flimsy, and I think there is a human tendency to protect that hard-earned territory, with which AG is not burdened. In the variation I will show White playing a defensive move. ]
;B[mo]C[When Black pushes through here, it is already difficult for White to find a satisfactory way to surround the territory. ]
;W[cm]LB[dh:A][fl:B]C[White just plays away to the left side. This is a huge move, and for now at least, Blacks group in the corner is in trouble. White has a cut at A, which is miai with pushing through at B, so Black is cut off. ]
;B[mq];W[lq];B[fg];W[ef];B[di]
(;W[rb]C[White has a lot of aji with this kaketsugi in the UR corner, but it comes as a suprise to me that White did not continue on the left side instead of this move (see var). ]
(;B[lo]TR[ji]C[Trying to kill White in the upper right corner is a bit complicated, so in the case of a human player that would be reason enough for Black to play away. Pushing into White's side area brings the marked Black stones into the action while reducing White's territory. So, what about those big moves in the LL and LR corners that I mentioned earlier? It all links up later in the game, and in a suprising fashoin, so we have to wait. ]
;W[ob]C[Now White is alive in the corner. ];B[nb];W[oc];B[sd];W[rc];B[od];W[nd]
;B[lc];W[na]TR[jc]LB[pb:A]C[White's hane prevents the killing move Black A, and sets up to save the marked cutting stones. ]
;B[jl]LB[jl:A][mq:B]C[Locally, Black jumping at A might look unreasonable, but this links up to the lower side, where the stone at B is a thorn in White's side. ]
;W[km];B[mr];W[mp];B[jm]
(;W[jn]TR[ji][jl]C[White plays a hane to cut Black off, but Black will have have opportunities to make a seki in the center, so this move does not actually capture the marked stones outright. The alternative for White is to extend and cut Black off with a connected shape for White (see var). ]
;B[kn];W[jo]
(;B[fq]C[Black finally plays in the LL corner, and this Black group is not completely dead yet. As I mentioned in my comment at move 128, Black can get a seki in the center, so in the var I will show that sequence. ]
(;W[lb]LB[jc:A][fq:B]C[White connects up with the stones at A, cutting off Black's side group. One might ask, why does White play away when Black has just pushed through at B, and I have tried to answer that in the var. ]
;B[mc];W[kc];B[le];W[ma]TR[ib][gd]LB[ma:A][db:B][kl:C]C[With the sequence to A, White saves White's stones on the upper side and cuts off Black's marked group. That means that White can next play at B to surround the upper side with White B, a huge move. The play at B is about the same size as a White play at C, so these two points could be called miai. The LL and LR corners are big too, but as I tried to show with a var for White 132, everything on the lower side is interconnected in a way that makes it hard for White to find a satisfying move in that area, and that is a reason for White to be playing away from the lower side to take the big point at A. ]
;B[ps];W[nq];B[gr]TR[dq]C[With this move, Black will be able to live with the group in the LL corner. White's marked stones are not dead yet, so the next move in this is still big.]
;W[kl]C[White captures Black in the center. ];B[or];W[ns];B[sr]TR[lp][mp][nq]LB[sr:A]
[eb:B]C[With the play at A Black is aiming to get a seki, with some extra potential for a ko that we will see in the game variation. Making a seki in the LR corner is just about 25 points, making it smaller than a Black play at B to connect on the upper side, but there is some added value for Black on the lower side that makes it good for Black to choose the LR corner even though it is smaller in territory. White's marked group is not yet alive, so Black will get a valuable forcing move against this group. ]
;W[er];B[fr];W[bq]LB[bq:A]C[White lives in the corner with A, which is worth about 25 points when compared to Black capturing White in this corner. The added value is that Black's group here is not clearly alive yet. ]
;B[jq]TR[lp][mp][nq]LB[sr:A]C[This move puts White's marked group in danger while reinforcing Black's group on the left. This was the bonus that Black got for making a seki with A. ]
;W[kp];B[ic]LB[eb:A]C[Black connects, with the intention to force once before connecting with A. ]
;W[sn]LB[sn:A][si:B]C[Locally, White A is a forcing move, because if White plays at A next, the semeai will favor White. ]
;B[cp]LB[sj:A][cp:B]C[It seems typical of AG not to immediately answer at A. With B, Black is threatening to kill White in the LL corner. ]
;W[cq];B[em]C[Now White's group on the left is in danger. ];W[kb];B[eb];W[cj];B[oi]
;W[oj];B[bn];W[fl];B[hq];W[el];B[sj]LB[or:A]C[Finally Black returns to the right side. Black has at least a seki, with some extra potential with the ko at A. ]
;W[hp];B[ir];W[bm]LB[dp:A]C[White threatens to cut at A. ];B[dp];W[sk];B[si];W[bh]
LB[or:A]C[Finally this looks like a normal endgame. The final complication will be the ko at A, which starts in about 30 moves. The ko is not an immediate threat because Black needs two set-up moves to get a direct ko. ]
;B[bg];W[ch];B[dh];W[fc];B[fb];W[mm];B[bp];W[bs];B[kr];W[lr];B[fi];W[sc];B[qf];W[gh]
;B[fh];W[gi];B[gj];W[gk];B[fj];W[hi];B[ip];W[io];B[jp];W[ko];B[ln];W[nk];B[ec];W[se]
;B[sf];W[fd];B[gc];W[ci];B[rq]LB[rq:A][sm:B]C[Black A is the first set-up move to start this ko, and Black will need to play another move at B (while fighting the ko) to get a direct ko. ]
;W[pr];B[so];W[sp];B[or];W[lf];B[mf];W[pr];B[fe];W[gf];B[ed];W[nm];B[or];W[pi];B[oh]
;W[pj];B[ph];W[oo];B[on];W[pr];B[dj];W[bk];B[or];W[hr];B[hs];W[pr];B[ck];W[dk];B[or]
;W[qe];B[pe];W[pr];B[ah];W[or];B[bj];W[cl];B[ai];W[en]LB[ai:A][en:B]C[White finished the ko, and Black got the big move at A. White B is also a big move at this stage of the game, and it seems that this exchange was well played. After this, the play is straighforward, but the result is special. ]
;B[pc];W[pb];B[dn];W[dm];B[fo];W[fn];B[ks];W[db];B[da];W[cn];B[oa];W[ek];B[go];W[ho]
;B[ls];W[ms];B[mb];W[la];B[ap];W[rg];B[sd];W[an];B[ao];W[bo];B[se];W[bn];B[aq];W[ar]
;B[ja];W[pa];B[ka];W[qa];B[pk];W[ok];B[jb];W[oa];B[es];W[ds];B[fs];W[lm];B[pm];W[mg]
;B[md];W[kg];B[lg];W[ej];B[do];W[ak];B[bi];W[ck];B[gg];W[be];B[bd];W[qh];B[ge];W[nf]
;B[me]
(;W[so];B[sm]C[This is actually a half point win for White when counted using the Japanese rules, but AG uses Chinese rules, with which Black wins by one fourth of a stone. This is an unusual margin for a Black win with Chinese rules, because Black's smallest winning margin is almost always three fourths of a point. This has to do with the dame at A, which is inside a seki, and filling it would be a losing move for either side. In the Chinese rules, when a stone cannot legally be put on the point, the players split the value of this point and share it, and this results in the unusual margin of victory. This is also a rare case in which Japanese rules and Chinese rules will not give us the same win/loss result. ])
(;W[aj];B[ag]
(;W[so];B[sm];W[np];B[qg];W[pl];B[rh];W[ei];B[ae];W[hk];B[ee];W[eo];B[kq];W[sl]
;B[ss]C[ B+0.25
(Japanese rules W+0.5)])
(;W[kq];B[eo];W[ae];B[ad];W[ei];B[af];W[hk];B[ee];W[pl];B[sg];W[np];B[sh];W[so]
;B[sm];W[sl];B[ss]C[B+0.25 (W+0.5)])))
(;W[fr];B[gr];W[er]LB[gr:A][er:B][hr:C]C[When Black cuts at A, White really wants to be able to connect at B. If White instead plays at C, then it will be easy for Black to live in the corner. ]
;B[ho];W[go];B[np];W[nq];B[kl];W[lm];B[ll]TR[mq]LB[gr:A][ho:B][ll:C]C[White's cut at A has made the peep at B forcing, and this peep is the decisive move. In combination with some aji the marked stones, Black has already killed White in the center when Black plays at C, as the rest of this variation will show. ]
;W[mk];B[lr];W[kr];B[jp];W[kq];B[in]TR[jn]C[Black captures the marked cutting stones. In this variation the LL corner, the LR corner and the center link up in an amazing way, ]))
(;B[lk];W[kl];B[kk];W[mk];B[ll];W[lm];B[nk];W[mj];B[nl];W[mm];B[oi];W[ik];B[jk]
;W[im];B[nm];W[il];B[nj];W[ii];B[ln];W[ij]TR[pi][oj]LB[oi:A][fl:B]C[Black can make a seki in the center with this sequence. This is just one of many possible variations in the center, but I will call this the main and representative variation. Black gets some extra profit by making the marked territory, and locally this is a success for Black. The problem with this line of play for Black is that White will not immediately play this sequence to the end. White's group in the center is just 12 stones, making it about the same size as capturing Black in the LR corner. So, about when Black plays at A, White can just leave the center and capture the LL corner with B. The center and the LR corner are miai, and White has a lead in territory. ]))
(;W[kn];B[ko];W[jn];B[np];W[nq];B[lr];W[ps];B[ms];W[kr];B[kq];W[sr];B[ss];W[sn]
;B[kp]LB[kn:A][np:B]C[White can capture Black in the center with A, but Black then pushes through at B, and the lower side falls apart. White can get a ko in the corner, but Black has already taken profit on the side, and has a number of ko threats that will be good enough to secure a win for Black. ]))
(;B[pb];W[pc];B[ob];W[qe];B[rf];W[oh];B[oi];W[qf]LB[rg:A][od:B][kg:C][pi:D]C[If Black tries to kill White in the corner, there is a great deal of bad aji in this variation. With the immediate threat of White A or B, and some aji with a cut at C or the atari at D, this looks troublesome for Black. ]))
(;W[fl];B[lo];W[km];B[mr];W[mp];B[ps];W[nq];B[sr];W[sn];B[or];W[ns];B[sj]TR[qc]
[rd][fm][co][ep]LB[fl:A][sj:B][or:C]C[Pushing through at A seems to be the natural move. The sequence to B gives Black a seki, with a one-sided approach ko for Black. With this I mean to say that Black can fill White's liberties while fighting the ko at C, and with enough ko threats will eventually be able to kill White, but the best White can get is a seki. Looking at the game position, there is still a lot of aji attached to both of the marked groups, but if we assume that both groups die the game is close. ]))
(;W[mo];B[np];W[mq];B[fg];W[ef];B[dm]LB[mo:A][dm:B]C[If White plays at A, White's side area will be safe, and now Black can get no more than a seki in the LR corner, so locally this is an important move. However, when one looks at the overall position, this is just not good enough for White. Black will get most of the left side after playing at B, and Black is ahead. ]))
(;B[rr];W[sq];B[qs];W[sp];B[sr];W[sn];B[sj]TR[pn]C[Black can get a seki with this sequence. This is worth almost 25 points, but is small at this stage of the game. A fine point is that if White kills the Black corner group, then the two marked stones will become dispensable, which is an advantage to Black, but when Black spends a move to create a seki, Black must save the marked cutting stones to maintain that seki. This is one factor that reduces the value of making this seki for Black, as Black would like to have the option of being flexible and sacrificing the two stones in some cases. ]))
(;W[rr];B[rs];W[sr];B[sp]LB[sr:A][qs:B]C[Black has a five stone nakade shape, and is already winning the semeai. Wjite could have played A at B to get a ko, but that one-sided ko would be good for Black. ]))
(;W[pm];B[om];W[rl];B[qk];W[rp];B[rq];W[rk];B[qj];W[ro];B[os];W[rj];B[qi];W[jc]
LB[pm:A][rl:B][rp:C]C[It is correct for White to cut at A, the idea being to crawl at B with sente and then have time to play the hane at C, which is an important point in this fight. White gets sente to play on the upper side, and this is an even result. ])
(;W[rp];B[rl];W[rq];B[rr];W[ps];B[qr];W[ro];B[sm];W[sr]LB[rp:A][ps:B][sr:C]C[White's hane at A is maybe the most commonly played move in this shape, but it will lead to a ko that is annoying to White in this board position. White kills Black with B, and then plays the vital point at C, and if we just look at the number of liberties, White has 4 while Black has only 3, so White might seem to have an advantage in this semeai. However...]
;B[sq];W[sp];B[rn];W[pr];B[so];W[sn];B[fq];W[fr];B[so]LB[sq:A][fq:B]C[... Black can throw in at A to create this ko, and Black has some ko threats with B. White also has some ko threats, but while Black's ko threats starting from B are a valid sequence that will settle the Black group in the LL corner, White's ko threats in the UL corner are going to be a bad exchange for White. ]
;W[bg];B[bh];W[sn];B[gr];W[hr];B[so];W[dg];B[ch];W[sn];B[er];W[gs];B[so];W[be];B[ag]
;W[sn];B[cq];W[rm];B[dr];W[sl];B[gg]LB[bg:A][gg:B]C[White finally could win the ko by giving Black the LL corner. White's ko threats starting with A strengthened Black in the corner significantly, and it is now awkward for White when Black finally attacks at B. Black has a favorable position. ]))
(;B[qn];W[po];B[ro];W[rp];B[rq];W[rn];B[sp];W[on];B[pl];W[ql];B[pm];W[pk];B[nl]
;W[rm]LB[qn:A][rp:B][on:C][ql:D]C[If Black covers at A, White pulls back and cuts at B. Black will capture the cutting stone, following the Go proverb. White then gets to play the shape move at C, and continues with the tesuji at D. White has an advantage in this fight. ]))
(;B[df];W[cg];B[bg];W[ch];B[ef];W[cb];B[bb];W[eb];B[ca];W[eh];B[di];W[eg];B[gf]
LB[df:A][eb:B][eh:C]C[Cutting at A is the fighting way for Black to play. White reinforces the upper side with B before jumping at C. This fight will spread into the sides and center, and is about even. ]))
(;B[gp];W[hq];B[hp];W[ip];B[io];W[jp];B[cf];W[fc];B[di]LB[gp:A][di:B][fq:C]C[By pushing with A, Black continues in the plan to give the lower side to White on a limited scale, and Black builds a wall towards the left side. Black then continues to build a side area for the wall up to B. This seems a reasonable and logical sequence for Black, and I would probably play this way. In this sequence, I might also consider pushing through at C to cut on the second line at some point, which has its pros and cons, so stronger players might have fun experimenting with that idea. The teaching tool actually shows Black A as a move that AG likes, but gives a better score to the game variation. ]))
(;B[lp];W[qj];B[pq];W[qg]LB[lp:A]C[Even after AG, the pincer at A is still commonly played in pro games, and is about equal in popularity with the game variation. I still prefer this variation, as can be seen in Redmond Reviews episode 6, which can be found at the AGA channel on YouTube. ]))