(;GM[1]FF[4]SZ[19]AP[SmartGo:3.1.2]CA[utf-8]
PW[AlphaGo]
PB[AlphaGo]
KM[7.5]
RE[W+R]ZT[60]MU[0]
C[Commentary by Michael Redmond 9P];B[pd];W[dd];B[pq];W[dp];B[fc];W[cf];B[ql]
;W[qc];B[qd];W[pc];B[oc]
C[This version of AlphaGo often plays this hane, instead of the move at A that has become popular after AGZero. ]
LB[nc:A];W[ob];B[nc];W[nb];B[mc];W[mb];B[lc];W[fq];B[gp];W[fp];B[ol]
C[The AGMaster that played 60 games against human pros at the end of 2016 would have played at A with Black, while this later version of AGMaster seems to show greater flexibility in it's ability to delay the jump at A. ]
LB[gn:A];W[oe]
C[This peep is a move that is played in this self-played series, and  also by AGZero. If Black simply plays at A, this will be a profitable exchange for White. ]
LB[od:A];B[og]TR[lc:oc]
C[This is a position where Black had a number of choices, such as Black A. Compared to A, Black 23 puts a strong emphasis on surrounding the right side while attacking White, and pushing the White stone against the marked Black wall. Being parallel with Black's stone at B, this move creates a high position that will be hard for White to penetrate, and thus gives Black a good position on the right. ]
LB[nf:A][ol:B]
(;W[nh]
C[Cutting looks bad for White (see var), but still I doubt that I would have thought to play this shoulder hit on the 6th line. ]
;B[ng];W[lh];B[mg];W[nq]LB[qq:A]
C[White 28 is a commonly played good move that looks to exploit the aji of a tsuke at A. ]
(;B[lp]
C[When Black pincers, White will be able to trade and take the corner. The alternative for Black was to answer on the right (see var). ]
;W[qq];B[qp];W[pp]
(;B[rq]
C[Black plays an atari from the wrong side here, if one is to believe the basic joseki (see var). With the marked stones, Black has enough strength in the local area to make this a good move. ]
TR[ol][ql][lp];W[qr];B[op];W[po];B[oq];W[rp];B[qo];W[ro];B[qn];W[rr]TR[ol]
C[Usually it is painful to be playing so many moves on the second line, so this might seem to be bad for White, but the marked Black stone is not on the most efficient point, and this is about even. ]
;B[gn];W[mo];B[nr]
(;W[kk]
C[It is not good for White to continue on the lower side immediately (see var).]
;B[rd];W[rc]
(;B[kn]
C[Black expands the lower side and prepares to attack in the center. It is not good for Black to allow White to take this point (see var). ]
;W[mr];B[mp];W[ec]
(;B[mh]
C[Black 53 is actually a big move that expands the right side and prevents White from making a base for White's group in the center. ]
;W[od];B[rf];W[jd];B[jh];W[hk]LB[jd:A][jh:B][hk:C]TR[od:oe]
C[White exchanges A with Black B before escaping at C. White is going to make use of the marked stones to strengthen the stone at A. The effect is that White has reduced Black's potential on the upper side. ]
;B[fd];W[kc];B[lb];W[kb]
(;B[me]
C[Black must back off here, as stopping White's connection underneath was dangerous (see var). ]
(;W[fg]TR[kb:kc][jd]
C[White's marked stones can escape by connecting to the UR corner, So the idea of playing a forcing move to chase Black from the center first is natural. The suprise was in the placement of White's move, in a position where I would expect a direct capping move (see var). ]
;B[ef];W[dh];B[cg];W[dg];B[ce]
(;W[be]
C[White 70 was a sharp tesuji that avoids giving Black an easy life in the corner (see var). ]
(;B[cb]
C[It is not common to see a corner invasion on the second line! Black shows a double threat that is going to succeed in settling the weak Black group on the upper side. I have added two variations for Black pushing through on the 3rd line or trying to set up a 3-3 invasion instead. Both tries will fail. ]
(;W[df]
C[White backs off, and Black will now be able to connect and make a living shape in the upper left. The var shows what might happen if White tries to cut Black off. ]
;B[eb];W[db];B[da];W[la]
C[Playing away after wedging once at 74 is obviously a local mistake after Black captures at A, but AG doesn't care when the local area is not as important as the left side, and White will have a chance to return later and connect at A. ]
LB[dc:A];B[co];W[cp];B[bp];W[bq];B[cl];W[dc];B[gb];W[bc];B[hd];W[fm];B[bo]
;W[bk]
C[When White has a strong position in the upper left, it is correct for White to play on the second line here to reduce Black's eyespace. ]
;B[ck];W[cj];B[bl];W[bj];B[el];W[fn];B[br]LB[aq:A][do:B][em:C]
C[If White answers at A, Black can force with B and then play at C to make a living shape on the side. ]
;W[cq];B[dj];W[ej];B[aq];W[cr];B[ek];W[ge];B[ib];W[gd];B[id];W[jf];B[gc]
;W[jp]
C[Black is not yet alive on the left, but White is too weak in the center to kill Black with a move such as A. In the game sequence we will see White playing moves towards the right half of the board, indirectly using Black's weak group on the left to invade Black's area on the right. ]
LB[dn:A];B[gl];W[lo]
(;B[no]
C[Black cannot cover on the left with this move (see var). ];W[ko];B[hl]
;W[mm];B[hq]
C[Black enters the lower side, looking to attack on both the right and the left. ]
;W[or]TR[ko][op]
C[White 116 is a big move that gives a potential connection underneath for the marked White group, and also puts some pressure on the marked Black group by denying it a base on the lower side. ]
(;B[go]TR[el][gl][gn]
C[With Black 117, I can finally say that the marked Black group is all connected and strong. Black might even seem to have some ideas to attack White in the LL corner, but the game sequence will show us how that doesn't actually work out for Black. Meanwhile, White is all set to reduce Black's area on the right. Black did not even have a satisfactory way to surround that area by adding a move now (see var). ]
;W[nl];B[gr];W[fr];B[om];W[nj]
C[One must notice that White's marked group does not have any clearly defined eyes, and is not really connected to any friendly groups yet. Black A is a forcing move againts White's group in the LL corner, which adds to Black's attacking potential. Even so, it will be very difficult for Black to successfully attack. ]
TR[nj][kk][nl][mm]LB[ir:A];B[np];W[ns];B[jn]
C[Black 125 tries to set up an attack, and is also a big move in territory. White playing at the same point would have made some territory for White in the center. ]
;W[ok];B[pk];W[pj];B[qj];W[pi]
C[White just won't stop invading, and it becomes apparent that White is getting some potential eyespace at the marked point. ]
TR[oj];B[mk];W[nk];B[mj];W[mi];B[li];W[ni];B[lj];W[qi];B[rj];W[kq]
C[White 140 will not quite succeed in connecting White's weak group to the corner. In the process of getting cut off, White will get the right to play at A and B with sente, and this will give White some extra potential towards the center. ]
LB[nn:A][jo:B];B[fo];W[ar];B[as]
(;W[eo]
C[White doesn't play the easy move (see var). ]
(;B[kr]
C[This attachment is an unusual but highly effective way for Black to sever White's connection. Two vars are added to show some moves that might be more intuitive but are less effective for Black. ]
;W[qg];B[qf];W[lm];B[ir]
C[Black 149 is forcing against the corner, depending on a ko when Black plays at A. ]
LB[cs:A];W[dn]LB[cs:A]
C[White avoids the easy move at A, but gets some extra profit by saving the marked two stones. ]
TR[fm:fn]
(;B[kl]
C[The var shows how White is alive in the LL corner. ];W[jl];B[km];W[ll]
;B[lk]
C[Finally, White's big group is cut off. with only one eye at A. If we were to fix up Black's shape in the center and treat this as a simple life/death problem, there would be no way for White to make a second eye on the right side. In actual play, White can make use of the attempted connection at B to create forcing moves for White at C, causing some serious trouble for Black in the center. Even without that problem for Black, White has at least forcing moves at D and E, and a second eye will appear at the marked point. ]
LB[oj:A][lq:B][jo:C][nn:D][ln:E]TR[mn]
(;W[rg]
C[White 156 is not a serious attempt to create a second eye, but White is just gaining some territory before living as explained inmy comment at 155. A var has been added to show how White cannot make an eye on the right side. ]
;B[ei]
C[This is where Black seems to give up on the idea of killing White, and the endgame begins. White has a comfortable lead. Towards the end of the game we will see White do some strange things and lose several points in a ko, but anyone familiar with AG can take that as indication that White knew it was winning anyway. ]
;W[jj];B[kg];W[ih];B[ci];W[pf];B[pe];W[in];B[io];W[pg];B[of];W[jo];B[im]
;W[di];B[fj];W[bi];B[lr];W[oh];B[cs];W[eq];B[pr];W[ps];B[em];W[do];B[ee]
;W[rn];B[rm];W[fh];B[mq];W[bb];B[ds];W[es];B[hf];W[gf];B[hh];W[ji];B[jg]
;W[hi];B[ig];W[gi];B[en];W[ki];B[kh];W[sd];B[se];W[sc];B[ik];W[gk];B[jk]
;W[kj];B[lg];W[ij];B[il];W[qs];B[nr];W[cc];B[ca];W[nq];B[ii];W[hj];B[nr]
;W[ba];B[ea];W[nq];B[ke];W[je];B[nr];W[bm];B[cm];W[al];B[bn];W[am];B[cn]
;W[nq];B[dr];W[er];B[nr];W[ip];B[ar];W[dq];B[hn];W[nq];B[ln];W[mn];B[nr]
;W[sg];B[ne];W[nq];B[ak];W[aj];B[nr];W[fk];B[fl];W[nq];B[eg];W[eh];B[nr]
;W[ic];B[hc];W[nq];B[kd];W[jc];B[nr];W[ap];B[ao];W[nq];B[ap];W[bs];B[nr]
;W[nn];B[on];W[nq];B[cs];W[ds];B[nr];W[ml];B[lh];W[nq];B[ff];W[gg];B[nr]
;W[ga];B[ha];W[nq];B[fi];W[gh];B[nr];W[sf];B[nd];W[nq];B[ma];W[ka];B[nr]
;W[re];B[os];W[qe];B[an];W[ak];B[ri];W[or];B[pb];W[qb];B[os];W[jr];B[js]
;W[or];B[pa];W[qa];B[os];W[oe];B[od];W[or];B[ms];W[os];B[jq];W[hg];B[ie]
;W[ih];B[de];W[kp];B[sn];W[kf]
C[(W+1.25 stones=~3.5points)])
(;W[pg];B[pf];W[oh];B[qh]
C[Black A is the tesuji to take away White's eye here. ]LB[qh:A]))
(;B[cs];W[eq];B[dr];W[do]TR[dr]
C[Maybe you think that White has only half an eye? Actually, Black cannot save the marked stone, and that will become White's second eye. Just try to save that stone, and you will see Black fall one move short. ]
))
(;B[lq];W[kr];B[lr];W[ir];B[iq];W[jo]LB[in:A][gq:B][ls:C]
C[Black is burdened with weaknesses at A and B, and White also has a connection underneath at C. ]
)
(;B[kp];W[jo];B[jq];W[iq];B[jr];W[ir];B[kr];W[gq]LB[in:A][lq:B]
C[With weaknesses at A and B, Black is getting into trouble on both sides. ]
))
(;W[cs];B[ap];W[dr]LB[cs:A][dr:B][do:C]TR[fm:fn]
C[Just to show an answer to the tsumego problem, White can make a living shape with the forcing move at A, and then B, which will be a seki if Black continues. The drawback in a real game is that Black can play at C to capture the marked two stones to make a nice territory. ]
))
(;B[mk];W[rn];B[rm];W[pn];B[qm];W[om];B[on];W[nl]LB[mk:A][rn:B][rm:C]
C[Black A might seem to be a big move that surrounds the right side, and indeed this is the move that Black wants to be able to play. However, when White crawls at B Black is faced with the choice of losing several points on the side, or facing the tactic shown in this var when Black covers at C. ]
))
(;B[ko];W[np];B[no];W[mq];B[lq];W[lr];B[jq];W[oo];B[nn];W[or]LB[ko:A][np:B]
C[If Black covers at A, White will push through at B, and Black will have no choice but to sacrifice something. This var is good for White. ]
))
(;W[eb];B[cd];W[de];B[df];W[bf];B[bd];W[ch];B[ae];W[bg];B[ee];W[fb];B[gb]
;W[hb];B[gc];W[ga];B[hc];W[ib];B[ha];W[fa];B[ic];W[jc];B[dc];W[ed];B[db]
;W[ia];B[gf];W[la];B[gg]LB[eb:A][cd:B]
C[If White cuts Black off at A, then pushing through at B becomes an effective move for Black. In this var White gets pushed around a bit as Black lives in the corner and also gets good shape in the center. ]
))
(;B[cd];W[cc];B[bd];W[de];B[df];W[bf];B[bc];W[bb];B[cb];W[ad];B[dc];W[ac]
;B[eb];W[cc];B[ed];W[fm]
C[When Black pushes through at A, Black cannot brealk into the corner. The squeeze shown here is a well-know tesuji for White to capture the cutting stones. Although Black can live on the upper side, White's strong position will work well with White's moyo on the left, and this is good for White. ]
LB[cd:A])
(;B[df];W[bf];B[cc];W[cd];B[eb];W[db];B[dc];W[ed];B[cb];W[fb];B[da];W[gb]
;B[hc];W[hb]
C[In this var Black sets up a 3-3 invasion, which might be called the default plan when attacking a star point corner. In this case it is not good for Black, as Black's gain in territory is small when White later plays at A to squeeze the corner. Black's stones on the outside are weak. ]
LB[bc:A]))
(;W[de];B[df];W[bf];B[be];W[bg];B[cc];W[dc];B[cb];W[ae];B[cd];W[ee];B[ff]
;W[fe];B[gf];W[ge];B[hf];W[he];B[ie];W[id];B[ad];W[hh]
C[Black gets a big life in the corner, and has the bonus of a connection underneath later with A. It will be difficult for White to find an efficient way to surround the left side, and this var favors Black. ]
LB[fb:A]))
(;W[ff];B[ee];W[dg];B[de];W[ce];B[cc];W[cd];B[eb];W[db];B[dc];W[cb];B[ed]
;W[bc];B[ie];W[la];B[ik]LB[ff:A][ee:B][eg:C][ik:D]
C[If White simply caps at A, Black will play B and then reduce the corner with a standard 3-3 invasion, and a weakness in White's shape remains at C. Black finally attacks at D, and the fight continues. ]
))
(;B[ka];W[ja];B[la];W[ld];B[md];W[me];B[le];W[lf];B[ke];W[jf];B[jb];W[kf]
LB[lf:A][jf:B]
C[White can make use of Black's damezumari and squeeze with the tesuji at A and B. This is good for White. ]
))
(;B[fd]
(;W[od];B[rf];W[lg];B[lf];W[kf];B[le];W[mh];B[oh];W[nj]
C[Since White has a lead in territory, this looks good for White when the White group in the center becomes strong. ]
)
(;W[jh]))
(;B[gq]))
(;B[dg];W[cg];B[di];W[kn]LB[kn:A]
C[White A is a big move that reduces Black's potential on the lower side, and this is good for White. ]
))
(;W[mq];B[no];W[mp];B[lm]
C[Good for Black]))
(;B[qr];W[rq];B[op];W[po];B[oq];W[oo];B[np];W[qn];B[rr];W[rp]
C[While this was a joseki-like sequence, it was not a good choice for Black in this board position. Black's marked strong position has little value when the lower side is relatively small, and White's profit in the corner is superior. ]
TR[lp][np:op][oq:pq]))
(;B[op];W[pr]
(;B[qr]
C[Covering on the right is weak (see var for Black's stronger move). ];W[or]
;B[qp];W[kq]LB[op:A][pr:B][np:C]
C[If Black answers at A, White B is a sharp move. In this variation White gets a solid base on the side, and has reduced the value of Black pushing at C. This is good for White. ]
)
(;B[or];W[oq];B[nr];W[pp];B[qq];W[np];B[oo];W[qr];B[rr];W[no];B[on]LB[pr:A][or:B][mr:C]
C[Attaching at A, White was trying to play forcing moves from outside, but Black has countered strongly with B in an attempt to capture the corner efficiently. Covering at C now would not be good for White, so White will trade by living in the corner. ]
;W[rq];B[qp];W[rs];B[sr];W[sq];B[ps];W[ss];B[rr];W[sr];B[mq];W[lp];B[lq]
;W[kp];B[kq];W[jp];B[jq];W[rp];B[qo];W[ro];B[ip];W[qn];B[po];W[lm]
C[White has scooped out the whole corner, and this variation favors White. ]
)))
(;W[od];B[rd];W[rc];B[qf];W[me];B[jd]
C[White has little potential to gain much from this fight, as Black will get to surround both the right and upper sides. ]
))

