(;
ST[2]
RU[Japanese]
KM[6.50]
TM[60]
OT[4x30 byo-yomi]
PW[Wang Chen]
PB[Albert Yen]
WR[8d]
BR[7d]
DT[2019-06-08]
EV[WAGC]
RO[4]
WT[China]
BT[USA]
RE[W+Resign]

C[World Amateur Go Championship
White:  Wang Chen, 8D
Black:  Albert Yen, 7D
June 3, 2019, in Matsue, Shimane Prefecture, Japan
Commentary:  Albert Yen, 7D
Game editors:  Kiren Polara, Myron Souris

Albert Yen, who placed an outstanding 4th in this year's World Amateur Championship, gives us another enlightening commentary, this time of his 4th round loss against China's Wang Chen.  For the game moves, Albert also includes LeelaZero's (AI) winrates.

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.  To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/4.0/ or send a letter to Creative Commons, PO Box 1866, Mountain View, CA 94042, USA.];
B[pd]
C[46.5% (0.0%)
1.0k playouts

Note:  LeelaZero's winrate percentage above is the winning estimation for the player who just moved.  The parenthesized percentage is how much the winning estimation increased (or decreased) as a result of the given move.  The playout count (in this case 1000) indicates the number of Monte Carlo runs in the game tree search - very roughly speaking, the more playouts the better the estimation.

Be warned that the winrates in this game may not be completely accurate, because WAGC uses Japanese rules, which has a 6.5 point komi rather than LeelaZero's 7.5 point komi.  In a normal game this would barely make a difference, but because the margin of lead in this game is very small throughout one point can make a big impact.  In other words, Black's position is always better than what the winrate indicates.];
W[cp]
C[53.1% (-0.4%)
1.0k playouts];
B[pq]
C[47.2% (0.3%)
1.0k playouts];
W[cc]
C[51.9% (-0.9%)
1.0k playouts];
B[pn]
C[47.1% (-0.9%)
1.0k playouts];
W[fq]
C[52.9% (0.1%)
1.0k playouts];
B[nc]
C[47.6% (0.6%)
1.0k playouts];
W[hd]
C[52.0% (-0.4%)
1.0k playouts];
B[dp]
LB[do:B][dq:A]
C[48.4% (0.4%)
1.0k playouts

This is now a common move in the age of AI.  Both hanes are possible but generally White will play the lower hane.];
W[dq]
C[52.6% (1.0%)
1.0k playouts];
B[co]
C[47.4% (0.0%)
1.0k playouts];
W[ep]
C[52.8% (0.2%)
1.0k playouts];
B[do]
C[47.2% (0.0%)
1.1k playouts];
W[bp]
C[52.8% (0.0%)
1.1k playouts];
B[cq]
LB[bq:B][cr:A]
TR[bo]
C[47.8% (0.6%)
1.0k playouts

The cut is a good testing move.  If White simply plays at A then the block at B5 becomes sente.  If White captures at B then there's liberty shortage on the right side later (bad aji).];
W[bo]
C[52.5% (0.3%)
1.0k playouts

Thus the turn here is correct.];
B[cm]
C[47.9% (0.4%)
1.0k playouts];
W[cr]
C[52.0% (-0.0%)
1.0k playouts];
B[df]
C[48.1% (0.1%)
1.0k playouts];
W[ed]
C[51.9% (-0.0%)
1.0k playouts]
(;
B[di]
LB[cd:A]
TR[cm]
C[48.8% (0.7%)
1.0k playouts

The exchanges in bottom left are about even.  Black helped White strengthen the corner but got an extension (C7) in sente.

However, in the top left I missed an important exchange at A.]
(;
W[ql]
C[50.6% (-0.6%)
1.0k playouts]
(;
B[rn]
LB[qi:B][qj:A]
C[45.3% (-4.1%)
1.0k playouts

This is a slow move (as you can see Black's winrate dropped considerably).  Playing at A or B is normal.];
W[re]
LB[qi:A]
C[55.3% (0.6%)
1.0k playouts

Wang is one of the strongest amateur players in the world.  We can see his mid-tier pro level strength with this move.  I was not expecting this move during the game but actually this is AI's top choice (according to Wang he has seen this shape before).  I was expecting a normal extension at A.];
B[qe]
C[45.4% (0.7%)
1.0k playouts];
W[rd]
C[54.7% (0.1%)
1.0k playouts]
(;
B[rf]
LB[qg:A]
C[43.9% (-1.4%)
1.0k playouts

Since the ladder doesn't work for me I probably should have played at A (you will see the ladder later). 

Exercize caution when analyzing the winrate fluctuations in this corner.  Many variations involve ladders and we know how well AI read ladders.  :)];
W[qf]
C[56.5% (0.4%)
1.0k playouts];
B[qg]
C[49.7% (6.2%)
1.0k playouts];
W[pf]
LB[rh:A]
C[50.3% (-0.1%)
1.1k playouts

I should play the tiger's mouth here.];
B[rg]
TR[rh]
C[47.8% (-1.9%)
1.0k playouts

Shape mistake.  Playing the tiger's mouth puts Black at a better position to fight.  I confused this shape with another where a ko can develop in the corner.  In that case connecting would be better to save ko threats.  However, in this situation there is no ko in the corner.  Playing at S12 would have made the fight much more favorable for me.]
(;
W[qd]
LB[pc:A]
C[54.7% (2.6%)
1.0k playouts

This is a new move for me.  I thought White would play at A, but that ladder works for Black.];
B[pe]
C[45.4% (0.1%)
1.1k playouts];
W[pc]
C[54.7% (0.1%)
1.1k playouts];
B[ne]
LB[pb:B][oc:A]
C[39.1% (-6.2%)
1.0k playouts

According to LeelaZero I should've made an exchange at A with White B, but in the game I wanted to preserve that sente to threaten to clamp at B later.  However, this gives White a chance to play at A immediately.  (Wang didn't play like this, though.  He thought that strengthens my group).]
(;
W[of]
LB[oc:A]
C[59.9% (-1.0%)
1.0k playouts

This move is somewhat premature.  White has a simpler way to secure a small lead with A.];
B[nf]
C[38.9% (-1.2%)
1.1k playouts];
W[ph]
C[60.8% (-0.4%)
1.0k playouts];
B[qi]
C[40.4% (1.2%)
1.0k playouts];
W[ng]
C[58.2% (-1.3%)
1.0k playouts];
B[mg]
C[40.8% (-0.9%)
1.0k playouts];
W[nh]
C[59.6% (0.4%)
1.0k playouts];
B[oi]
TR[og]
C[41.9% (1.5%)
1.0k playouts

This is a tesuji aiming to exploit White's cut at P13.]
(;
W[pi]
LB[oh:A]
C[57.1% (-0.9%)
1.1k playouts

Simply connecting at A is what I wanted.];
B[pj]
C[39.3% (-3.6%)
1.0k playouts];
W[oj]
C[55.5% (-5.2%)
1.0k playouts];
B[pg]
C[45.9% (1.4%)
1.0k playouts

Before I played this move Wang had been playing very fast (spending around 10-20 seconds per move).  However, he paused for at least 5 minutes after seeing this move, so immediately I knew he had missed something.

What did he miss? We'll see in 2 moves.];
W[og]
C[55.3% (1.2%)
1.0k playouts]
(;
B[ni]
LB[mh:B][oh:A][pk:C]
TR[ph][pi]
C[41.3% (-3.4%)
1.0k playouts

He missed that I could come out here and kill the marked stones.  Connecting at A doesn't work (so White played at B in the game).

However, this is not the optimal move for Black (the top group is weakened).  Simply extending at C is better.]
(;
W[mh]
C[59.8% (1.2%)
1.0k playouts];
B[oh]
C[40.4% (0.3%)
1.0k playouts];
W[lg]
C[60.3% (0.8%)
1.0k playouts];
B[kd]
C[37.8% (-1.8%)
1.0k playouts];
W[le]
TR[nb]
C[57.6% (-4.6%)
1.0k playouts

This exchange is not good for White (but he was aiming for O18).];
B[ld]
C[41.6% (-0.8%)
1.0k playouts];
W[mi]
C[55.4% (-3.0%)
1.0k playouts];
B[qh]
LB[qh:B][nj:A]
TR[mj]
C[38.9% (-5.8%)
1.0k playouts

This was a big mistake.  Of course I should have extended at A.  I wavered between A and B for 5 minutes and after I played B I immediately regretted my decision.  I thought I might get a chance to play at N10 and double hane but in reality White will come back to the center immediately.];
W[nb]
LB[mb:A][ob:D][mc:B][oc:C][qc:E][mj:F]
C[59.1% (-2.0%)
1.0k playouts

A very deadly probing move.  Black can lose the game immediately if this move is not properly answered.

Common responses from A to D are possible, but C is best.  I played at E, which is locally the best move but loses sente.  I should have gotten sente here with C and gone back to F (which was my plan all along).  In the game I was too fixated on points in the upper right and I opted to play a tesuji (though in hindsight it yielded a suboptimal outcome).]
(;
B[qc]
LB[qb:A][oc:B]
C[33.6% (-7.3%)
1.0k playouts

Good tesuji but bad move in this game (AI is cruel :c).  After the game Wang said he actually missed this move.  If he had seen this then he would have played in the center immediately without the exchanges.

White also has to be careful here.  Playing at A doesn't work (B is the only move).]
(;
W[oc]
C[66.1% (-0.3%)
1.0k playouts];
B[nd]
C[33.9% (0.1%)
1.0k playouts];
W[qb]
C[66.2% (0.2%)
1.0k playouts];
B[mb]
LB[nb:B][qc:A]
C[34.0% (0.2%)
1.0k playouts

The probe at B resulted in an even trade (which is bad for Black because White was winning before that move).  Move A is a bad exchange for Black because it gives White at least 2 extra points in the corner and sente.  However, move B does guarantee that Black's top group is alive.];
W[mk]
C[66.1% (0.0%)
1.0k playouts

I felt the game was not favorable for me when this move was played.]
(;
B[kp]
LB[lp:B][lq:A]
C[32.1% (-1.9%)
1.0k playouts

I knew a move around A or B is more orthodox, but I wanted to play more aggressively since I was behind.  Of couse, in hindsight B was still better];
W[oq]
LB[kp:A]
C[67.6% (-0.3%)
1.0k playouts

The problem with A is that there is no way for Black to severely attack this stone.];
B[pp]
C[32.7% (0.3%)
1.0k playouts];
W[pr]
C[65.9% (-1.4%)
1.0k playouts];
B[qr]
C[34.1% (0.0%)
1.0k playouts];
W[mq]
LB[mo:C][mp:D][kq:B][lq:A]
C[66.4% (0.5%)
1.0k playouts

This group is hard to attack.  I thought that as A and B are bad, and C is unsatisfactory, I needed to find an elegant move in an attempt to muddy the water.  However, I should have played the long game with C or D.]
(;
B[ml]
LB[mp:A]
C[28.7% (-4.9%)
1.0k playouts

I wanted to make the game complicated so I played here.  I wasn't sure how to attack the bottom group. 

The AI suggests A.]
(;
W[nj]
C[72.0% (0.8%)
1.0k playouts];
B[ok]
C[26.4% (-1.5%)
1.0k playouts];
W[pi]
C[77.4% (3.9%)
1.0k playouts

I didn't consider the aji here.];
B[ph]
C[22.7% (0.2%)
1.0k playouts];
W[pk]
C[78.6% (1.3%)
1.0k playouts];
B[qk]
C[22.6% (1.2%)
1.0k playouts];
W[nl]
C[76.9% (-0.4%)
1.0k playouts];
B[pl]
C[23.2% (0.2%)
1.0k playouts];
W[ll]
LB[ph:4][pi:3][nj:1][ok:2][pk:5][qk:6][ll:9][nl:7][pl:8]
C[77.4% (0.6%)
1.0k playouts

Overall result was still terrible for Black.  White gained a few moves in the center and I got very little on the right side.

Again, Wang played like an AI from O10 to this move.];
B[mm]
C[22.2% (-0.5%)
1.0k playouts];
W[lm]
C[78.4% (0.6%)
1.0k playouts];
B[ln]
C[23.1% (1.5%)
1.0k playouts

There aren't really any choices for both sides in the following 10 moves.];
W[mn]
C[76.4% (-0.6%)
1.0k playouts];
B[nm]
C[23.7% (0.0%)
1.1k playouts];
W[lo]
C[77.4% (1.1%)
1.0k playouts];
B[kn]
C[22.6% (-0.0%)
1.1k playouts];
W[ko]
C[77.4% (-0.0%)
1.0k playouts];
B[jo]
C[23.4% (0.8%)
1.0k playouts];
W[jn]
C[77.2% (0.6%)
1.0k playouts];
B[km]
C[22.8% (0.0%)
1.1k playouts];
W[nn]
LB[in:A]
TR[kp]
C[80.6% (3.3%)
1.0k playouts

I was a little bit afraid that Wang would extend at A and fight, but he thought he could be happy with just killing the L4 stone.];
B[om]
C[19.4% (-0.1%)
1.1k playouts];
W[jp]
C[75.9% (-4.7%)
1.0k playouts];
B[io]
C[24.4% (0.3%)
1.0k playouts];
W[lp]
C[77.0% (1.4%)
1.0k playouts];
B[jm]
C[22.9% (-0.1%)
1.0k playouts];
W[kk]
C[76.7% (-0.4%)
1.0k playouts];
B[ip]
C[23.6% (0.3%)
1.0k playouts];
W[kq]
C[76.7% (0.3%)
1.0k playouts];
B[ik]
LB[hl:B][il:A]
C[23.2% (-0.2%)
1.0k playouts

This is the wrong shape.  A or B is proper.  I never considered the possibility of the cut, but in reality it is quite severe.];
W[il]
LB[jl:A]
C[78.3% (1.5%)
1.1k playouts

The normal response at A doesn't work.

Wang played this move instantly and I am once again impressed by his intuition.]
(;
B[im]
C[21.1% (-0.5%)
1.0k playouts];
W[hl]
C[78.9% (0.0%)
1.0k playouts];
B[jl]
C[23.5% (2.4%)
1.0k playouts];
W[jk]
C[76.6% (0.0%)
1.1k playouts];
B[ij]
C[23.4% (-0.0%)
1.0k playouts];
W[hm]
LB[ji:A]
C[67.8% (-8.7%)
1.0k playouts

Even still, I actually have multiple chances in this fight to turn the game around.  This peep was a mistake.  Simply jumping at A is better (according to LeelaZero).]
(;
B[hn]
C[33.4% (1.3%)
1.0k playouts];
W[fm]
C[66.7% (0.1%)
1.0k playouts]
(;
B[lj]
LB[fn:A]
TR[lj][hm][hn]
C[29.5% (-3.8%)
1.0k playouts

For example, I should have attached at A immediately here.  White's turn at H7 was not good.

This is in AI terms, of course.  In reality I was aiming to play at M10 before H6, but I was afraid that White can get the H6 exchange first (which Wang laughed off as "impossible").];
W[ji]
C[71.4% (0.9%)
1.0k playouts];
B[ii]
C[30.0% (1.4%)
1.0k playouts];
W[jh]
TR[kl]
C[69.8% (-0.2%)
1.0k playouts

White has an imminent liberty shortage in the center, but there is nothing I can do to exploit it at this time.  Also note that White doesn't want to make the L8 atari unless it's absolutely necessary (it is a bad exchange).]
(;
B[fn]
C[31.8% (1.7%)
1.0k playouts]
(;
W[ei]
LB[en:A]
C[69.0% (0.9%)
1.0k playouts

I was almost in byo-yomi at this point and had no idea how to respond to this move (I only thought of A).  This is actually also Leela's first choice move...

Wang explained later that he didn't feel very confident about continuing the game peacefully, although he understood that White is not in a bad position here.  This being the case, he decided to take some risks and play a complicated move.];
B[li]
C[25.6% (-5.3%)
1.0k playouts

This is a terrible move.  I guess I was too dumbfounded by E11.];
W[mj]
TR[li][lj]
C[75.0% (0.6%)
1.0k playouts

After this exchange the 2 marked stones are dead.];
B[ih]
C[25.9% (0.9%)
1.0k playouts];
W[jg]
C[74.8% (0.7%)
1.0k playouts]
(;
B[ej]
LB[em:A]
C[21.6% (-3.7%)
1.0k playouts

I can complicate the game more with A, but either way the fight favors White.  The game is a straight path to defeat.];
W[fj]
C[79.4% (1.0%)
1.0k playouts];
B[fi]
C[20.8% (0.2%)
1.0k playouts];
W[eh]
C[79.2% (-0.0%)
1.0k playouts];
B[dh]
C[15.8% (-5.0%)
1.0k playouts];
W[eg]
C[79.4% (-4.8%)
1.0k playouts];
B[dg]
C[11.0% (-9.5%)
1.0k playouts];
W[en]
C[88.7% (-0.2%)
1.0k playouts];
B[gm]
C[10.5% (-0.7%)
1.0k playouts];
W[gl]
C[89.8% (0.3%)
1.0k playouts];
B[gn]
C[9.6% (-0.6%)
1.0k playouts];
W[fk]
C[91.7% (1.3%)
1.0k playouts];
B[eo]
C[8.6% (0.3%)
1.0k playouts];
W[fo]
LB[gi:A]
C[85.6% (-5.7%)
1.7k playouts

Unnecessary move.  Capturing at A is enough.];
B[em]
C[14.7% (0.3%)
1.5k playouts];
W[dj]
C[84.1% (-1.3%)
1.0k playouts]
(;
B[cj]
LB[ef:A][fl:B]
C[8.4% (-7.6%)
1.0k playouts

Final losing move.  My last chance to fight is to capture at B or escape at A.  With this move the center is essentially dead and the game is decided.];
W[el]
C[88.5% (-3.1%)
1.0k playouts];
B[fl]
C[11.7% (0.2%)
1.0k playouts];
W[ek]
C[88.6% (0.3%)
1.0k playouts];
B[ck]
C[6.2% (-5.2%)
1.0k playouts];
W[fm]
C[94.6% (0.8%)
1.0k playouts

The game is already decided at this point.  I started the ko later but White has multiple ways to win.];
B[jj]
C[5.6% (0.2%)
1.0k playouts];
W[kl]
C[95.2% (0.8%)
1.0k playouts];
B[in]
C[4.8% (-0.0%)
1.1k playouts];
W[kj]
C[95.6% (0.4%)
1.0k playouts];
B[fl]
C[4.7% (0.3%)
1.0k playouts];
W[jc]
C[93.3% (-2.0%)
1.0k playouts];
B[bq]
C[5.7% (-1.0%)
1.0k playouts];
W[br]
C[94.5% (0.2%)
1.0k playouts];
B[gk]
C[5.0% (-0.5%)
1.0k playouts];
W[fm]
C[95.2% (0.2%)
1.0k playouts];
B[dr]
C[5.7% (0.9%)
1.0k playouts];
W[eq]
C[94.7% (0.3%)
1.0k playouts];
B[fl]
C[5.4% (0.0%)
1.0k playouts];
W[kb]
C[94.5% (-0.2%)
1.0k playouts];
B[hk]
C[6.7% (1.1%)
1.0k playouts];
W[jd]
C[95.6% (2.2%)
202k playouts

The top group is dead and the game is over.  Following moves omitted.

Though I lost this game I think I performed pretty well and played at my level (unfortunately for my score Wang also played at his level :P).  I really felt a strength difference.  Wang is so keen on local variations and so sharp on shapes.  What impressed me the most was him spotting the cut at J8 within 3 seconds.  I really learned a lot from this game. :)]
)
    (;
    B[ef];W[ek];B[gf]
    C[This can complicate the game.]
    )
    (;
    B[fl];W[el];B[ef];W[fm];B[dm];W[fg];B[ig]
    C[Something like this would also give me more chances.]
    )
)
    (;
    B[em];W[dh];B[eh]
    C[There are still many unsettled parts.]
    )
)
    (;
    W[en];B[gm];W[gl];B[gn]
    (;
    W[el];B[eo];W[fo];B[dm];W[em];B[go];W[fp];B[dk]
    TR[el]
    C[This was my plan.  Unfortunately I was too naive.  E8 was a bad move for White and Wang would never play there.]
    )
        (;
        W[fk];B[em];W[gi]
        C[White can still maintain the upperhand in this fight.]
        )
    )
)
    (;
    B[lk];W[kl];B[in];W[kj]
    C[Doesn't work for Black.]
    )
    (;
    B[jj]
    C[Clever idea, but...]
    (;
    W[kl]
    C[White can atari first.];
    B[in];W[kj]
    )
        (;
        W[kj]
        C[If White is careless and blocks here];
        B[lk]
        C[Black can capture the two key stones and connect.]
        )
    )
)
    (;
    B[fn]
    C[This is my chance.];
    W[en];B[gm];W[gl];B[gn];W[el];B[eo];W[fo];B[dm];W[em];B[go];W[fp];B[dk]
    C[This is my chance.

In the game I played a few probing moves first because I had not yet fully read out these variations.  I was still thinking about different moves to liberate the bottom group.]
    )
)
    (;
    B[lj];W[hn];B[lk];W[in];B[kl]
    TR[hn]
    C[I thought this exchange was bad for Black, but actually Black gained (Wang said he would never think about playing H6 without responding to the peep first).]
    )
)
    (;
    B[jl];W[jk]
    (;
    B[hl];W[im];B[in];W[hm]
    C[The ladder favors White.]
    )
        (;
        B[hk];W[in]
        TR[io][jo][ip]
        C[If Black extends here White can kill the bottom 3 stones.]
        )
    )
)
    (;
    W[nl];B[nk]
    C[I was secretly hoping for this variation.  Black can cross cut and start a favorable fight.]
    )
)
    (;
    B[lq];W[mo];B[ln];W[mn];B[lm];W[mm];B[ll];W[ml]
    C[White connects to the main group and Black's group is now separated.  This is terrible for Black.]
    )
    (;
    B[kq];W[mo]
    C[This is also bad for Black for the same reason as the last variation.]
    )
    (;
    B[mp];W[np];B[no];W[lp];B[mo];W[lq];B[lo];W[jr]
    LB[cd:C][no:B][mp:A]
    C[I thought about the attachment at N4 but I didn't consider the double hane (B) so I thought Black would get gote here (power of AI).  With this variation I can go back to C and it is still anybody's game (White is slightly ahead but only by a small margin).]
    )
)
    (;
    B[lp]
    C[This extension is more standard.]
    )
)
    (;
    W[qb];B[pb]
    (;
    W[oc];B[ob];W[rc];B[od]
    C[White has failed.]
    )
        (;
        W[rc];B[oc]
        TR[nb]
        C[O18 becomes an useless move now.]
        )
    )
)
    (;
    B[mb]
    C[This might seem like the normal response, but it is catastrophic for Black.];
    W[od];B[oe];W[nd];B[md];W[oc];B[me];W[mc]
    C[Black crumbles.]
    )
    (;
    B[mc];W[oc];B[od];W[mb];B[lb]
    C[This is a similar result from A.  White gains a lot in sente.]
    )
    (;
    B[oc];W[ob];B[oe];W[qb]
    LB[lj:B][mj:A][lk:C]
    C[Best answer for Black.  I can get sente to play at A next.  Though White has gained a lot locally Black can easily make that back with A.]
    )
)
    (;
    W[oh];B[mh]
    C[It is not hard to see that White is dead here but this is hard to read out.  Black seems to have many cutting points but as White has only 2 liberties there is nothing for White to do.  Please verify this yourself as reading practice :]
    )
)
    (;
    B[pk]
    C[The patient move.];
    W[nj];B[oc];W[pb];B[rb];W[ob];B[nb];W[rc];B[qh]
    LB[rf:A][rg:B]
    C[Black would have recovered from the mistakes at A and B with this variation.]
    )
)
    (;
    W[oh];B[pg];W[og];B[pi]
    C[This is disastrous for White.]
    )
)
    (;
    W[oc];B[nd];W[oi];B[og];W[oq];B[pp];W[nl]
    C[This variation is the most risk-free for White.  White has a 62% winrate right now (which translates to a small fuseki lead).]
    )
)
    (;
    W[pc];B[qc]
    LB[qb:A][qd:B]
    C[A does not work for White, and Black is satisfied with B.

A ko can develop with A if the ladder works for White.];
    W[qb]
    (;
    B[pb];W[oc];B[ob];W[od];B[oe]
    C[This ladder works for Black.]
    )
        (;
        B[qd];W[rc];B[pb];W[oc];B[rb];W[od];B[qa];W[pe];B[qb];W[ob];B[oe];W[of];B[ne];W[sb];B[nd]
        LB[ra:C][rg:A][rh:B]
        TR[qb]
        C[Now White can throw in at C to make a ko, and if A is at B then White has a local ko threat.  However, R18 doesn't work for White right now, so connecting at A is just a big mistake.]
        )
    )
)
    (;
    B[qg];W[qc];B[cd];W[dd];B[ce];W[bc];B[lp]
    C[This is still an even game.]
    )
)
    (;
    B[qj]
    (;
    W[pp];B[qp];W[qo];B[po];W[op];B[qq];W[qn];B[pm];W[pl];B[nn];W[rk];B[np]
    C[This is a popular AI joseki.]
    )
        (;
        W[ol]
        C[This is a more peaceful response.];
        B[qm];W[rm];B[rn];W[op]
        C[A good move to make the corner overconcentrated.];
        B[oq];W[np];B[nq];W[mp];B[lr];W[pm];B[qn];W[on];B[nm];W[om]
        C[Much better for Black than the game.  Black can tenuki locally after this.]
        )
    )
    (;
    B[qi];W[pp]
    C[White might also play here.  The variations are complicated but it's roughly an even fight.]
    )
)
    (;
    AE[bo][co][do][bp][dp][cq][dq][cr]
    C[The shape is roughly like this, with Black making a few bad exchanges.];
    W[];B[co];W[bp];B[do];W[bo];B[dp];W[dq];B[cq];W[cr]
    LB[bo:4][co:1][do:3][bp:2][dp:5][cq:7][dq:6][cr:8]
    C[Black 1 and White 2 are not bad exchanges for Black, but 3, 5, and 7 are clearly bad for Black.]
    )
)
    (;
    B[cd];W[dd];B[ce];W[bc];B[di]
    C[This exchange helps Black solidify the left side and should be played immediately.  I wasn't aware of this possibility in the game but Wang showed me afterwards.  If Black makes this exchange early White has no choice but to give in.  Black should find a chance to come back to this as soon as possible (I didn't in the game because I didn't know that C16 existed).]
    )
)

