(;GM[1]FF[4]SZ[19]AP[SmartGo Kifu:4.8]CA[UTF-8]
GN[TPGL]
PW[Calvin Sun]WR[1p]
PB[Oscar Vazquez]BR[6d]
DT[2021-07-10]
PC[OGS: https://online-go.com/game/35187828]
KM[6.5]
RE[B+R]
RU[Japanese]
TM[1800.0]OT[3x30 byo-yomi]
C[Review by Antti Törmänen 1p]CH[1];B[pd];W[dp];B[pp];W[dc];B[de];W[ce]
;B[cf];W[cd];B[df];W[fc];B[dj];W[qq];B[qp];W[pq];B[op];W[nr];B[pj];W[mq]
C[The game starts with black forming influential positions on the left and right sides, while white secures early territory in the upper-left and lower-right corners.]
;B[cn]
(;W[mo]LB[mp:A]
C[White disliked getting flattened by black A, and therefore played this jump. See variation.]
;B[pm]
C[Black defends patiently, preventing white from starting a splitting attack on the right side. Usually tenuki to A would be more recommendable, as black's right-side position is quite flexible, but even then q7 is quite a fine move.]
LB[fq:A];W[fq]
C[Now white arguably got what he wanted on the lower side, since black A has been prevented.]
LB[mp:A];B[mc];W[bp]
C[White secures his third corner territory, and…];B[en]
C[…black keeps on improving his outer influence. Now the game is starting to get polarised, with white mostly having territory and black mostly having influence. The key decisive factor of the game will be if and how black will be able to transform his influence into territory.]
;W[cl]
C[White challenges black's left-side formation.];B[co]LB[bn:A][cp:B][el:C][ci:D]
C[This black peep prevents white's connection underneath at A. Usually white responds with B for a solid corner shape, black plays C, and then white continues his invasion with a move such as D.]
;W[bh]LB[cp:A][el:B]
C[Usually white would at most consider A and B. B12 aims to settle quickly on the left side without looking to put pressure on the black groups themselves. B by comparison would be helping the white stone at c8 while also cutting black's groups.]
;B[cp];W[cq];B[ch]
C[Black keeps on playing solidly.];W[el]LB[ci:A][di:B][cj:C][bh:D][ch:E]
C[White's earlier play suggests white should continue with A-B-C instead, aiming to live on the left side. By playing e8 now, D-E has become an exchange that mainly makes the black group stronger.]
;B[dq];W[dr];B[bq];W[cr];B[gn]LB[br:A][bs:B][bo:C]
C[A-B-C would also not be small territorially, but black still continues with his influence-oriented play. A-B-C will provide emergency eyes for the black group if necessary, so now black's fighting position is actually very strong.]
;W[fk]LB[gn:A][ch:B][ci:C][di:D][cj:E]
C[Now that both of black's left-side groups have become strong, it would make even more sense for white to go back to living on the left side with C-D-E.]
;B[gp];W[br];B[qf]LB[bi:A]
C[R14 is certainly a big move, but black should probably also prioritise A here, securing some territory while also preventing white from forming an eye base on the left side.]
;W[hm];B[gm];W[hk];B[io];W[ci];B[di];W[bj];B[cj];W[bi];B[bf]LB[dl:A]
C[This endgame move is sente, as black aims at cutting white with A next.]
;W[dm];B[ge]LB[gf:A]
C[If this move were left unplayed, a white move at A would quickly put black under pressure.]
;W[hd]LB[hc:A]
C[White prevents black from building territory on the upper side with A.]
;B[he];W[id];B[ie];W[jd]
C[After k16, the left-side fighting has more or less concluded, as all the involved groups have become strong.

A rough counting of secure territories gives us 39+komi for white and perhaps 27 points for black (imagining possible white invasions at A and B which cannot easily be captured). However, it is unlikely for white to get to play both A and B, so in reality black's territory is about is 10–15 points bigger (either A or B becomes black territory). We therefore still have an even game at hand.]
TR[aa:ha][bb][db:hb][cc][hc][ai:ak][bq][dq][ar:as][er:es][pr:ss][bs:ds][ns:os]
MA[qa:sd][re:se][qk:qo][rk:sn]LB[ob:A][qh:B];B[im]
C[J7 starts reinforcing the lower-side black group before white gets a profitable attack on it; this can be called a patient or confident way of playing.

Looking at the end result, however, in hindsight black may have preferred a slightly more territorially active defence such as A instead.]
LB[gq:A];W[eo];B[ep];W[fp];B[fo];W[eq];B[dn];W[hl];B[ko];W[hn];B[ho]
C[Finally, the lower-side black group still has somewhat awkward shape, and not even one secure eye for now.]
;W[gh]LB[dh:A][eh:B][cg:C]
C[This move sets up cutting points for the eventual A-B-C capture.];B[ih]
LB[eh:A]
C[Black A wouldn't have been a bad move either, but black instead chooses to defend proactively.]
;W[je]LB[jf:A][kf:B][jg:C][ih:D]
C[K15 takes some advantage of black's centre shape: now the black A hane becomes bad, as, if followed by B-C, then black D will be misplaced.]
;B[gj];W[fj];B[fi];W[gi];B[fh]LB[dh:A][eh:B][ih:C]
C[Finally black fixes the A cut in a different fashion, but ultimately it is difficult to say whether the exchange from C on was worth it or if it was best to play B immediately.]
;W[om]LB[hj:A][hi:B][hg:C]
C[Black A or white B looks big enough to take immediately, as it also refers to a cutting point at C and the stability of black's left-side group.]
;B[hj]LB[el:A]
C[Now in fact the white left-side group of A isn't 100% alive either. Black probably gets a small lead with this move, even if his right-side territory now has an opening.]
;W[fm];B[em];W[fl];B[fn];W[km];B[bl];W[bk];B[bm];W[ck];B[jm];W[ij];B[hi]
;W[kl];B[jk]LB[om:A]
C[An all-out battle erupts. The fact that A is still unanswered shows that it was clearly mistimed.]
;W[jl];B[il];W[ik];B[kk];W[lk];B[kj];W[ji];B[lj];W[dh]LB[ej:A][ei:B][dk:C]
C[White sets up a living sequence with A-B-C.];B[mk]LB[km:A][ko:B]
C[Black, in the meantime, attacks the A stones, since they affect his B group which is also under pressure.]
;W[kn];B[jn];W[mm];B[bo]
C[Now the lower-side black group is safe.];W[cg]
C[White is also virtually alive after this capture.];B[pl]TR[hi:hj][kj:kk][lj][jk][mk][bo]
LB[ei:A]
C[Black then finally returns to the right side, having made a considerable profit in the centre fighting with the triangle-marked stones. White has only gotten the prospect of the A cut, which is not quite a fair exchange.]
;W[fg];B[gg];W[eg]LB[ei:A][hh:B][ob:C]
C[Usually white should just force A-B here and switch elsewhere, for example at around C. However, now black is getting such a large territory on the right side that white probably cannot win by normal means; he instead tries to find a way to attack black in the centre.]
;B[dd]LB[ff:A]
C[This move is good if sente, but in this case there are complications involved. A instead would have been safest.]
(;W[cc]LB[gf:A]
C[White could have fought with A instead. See variation.];B[fd];W[gf];B[hh]
;W[fe];B[gd];W[ec]LB[gc:A][hf:B]
C[This move is close to a pass; white A, black B, and white tenuki is correct.]
;B[hf];W[ff];B[ed];W[gc]LB[ei:A][eh:B][ej:C][dg:D]
C[Ultimately, white makes a big loss here: now he no longer has the A cut available because of black's B-C-D refutal, and he even lost sente.]
;B[kg]LB[ei:A]
C[This move is basically sente, aiming to kill white with A next.];W[kh]
;B[lg];W[lh];B[jh];W[mh];B[mg];W[nh]
C[O12 searches for a last complication.];B[gk];W[gl];B[ki];W[mj];B[nj];W[mi]
;B[ll]LB[nk:A][nl:B][ok:C][ml:D][ol:E][nm:F][nn:G][ln:H]
C[White's plan was to use the A cut here, but it fails to B-C-D-E-F-G-H.]
;W[ei];B[eh];W[dg];B[ng]
C[O13 kills the white right-side stones, finishing the game.

Finally, it is almost possible to say that white A was the game-losing move, giving black a key opportunity to take hold of the fighting in the centre. Once black could finish the fighting in his favour, then returning to answer A with B, white was starting to fall too much behind on territory and had to resort to desperate means to try to stay in the game. This was a really convincing win for Oscar!

End of comments]
LB[om:A][pl:B];W[pc];B[oc];W[qd];B[pe];W[qb];B[ej];W[bg];B[ob];W[re];B[rf]
;W[rc];B[kq];W[ir];B[ap];W[rp];B[ro];W[rq];B[oq];W[or];B[jb];W[rn];B[qo]
;W[so];B[rm];W[sm];B[rl];W[qn];B[pn];W[ld];B[lc];W[ib];B[ac];W[ab];B[ae]
;W[bc];B[jc];W[me];B[hb];W[hc];B[ne];W[ia];B[ic];W[gb];B[jr];W[iq];B[lo]
;W[mn];B[ad];W[sf];B[sg];W[se];B[rh];W[bb];B[pb];W[qc];B[sl];W[md];B[nd]
;W[lr];B[hr];W[hq];B[is];W[gr];B[hs];W[gq];B[ar];W[sn];B[jf];W[oo];B[po]
;W[np];B[on];W[nn];B[lp];W[mp];B[kd])
(;W[gf];B[hg];W[fe];B[cc]
C[Black can cut here, but…];W[cb];B[bc];W[bb];B[ec];W[db]LB[de:A][gd:B][fd:C][gc:D]
C[…ultimately black has no way to form eyes for the A group, and he has to proceed to sacrifice it with B-C-D.]
))
(;W[fq]
C[For example, if white plays the usual joseki response in the lower-left corner…]
;B[mp]
C[…black may then aim to overconcentrate white on the lower side while increasing his outer influence.]
;W[lp];B[nq];W[lr];B[lo];W[kp];B[nc]
C[This is a possible follow-up. White's position probably cannot be called bad, but framework-oriented players would jump at the opportunity of getting to play as black.]
))

