(;
C[Low Dan Game
Commentary:  Yuan Zhou 7d
Game editors:  Bill Cobb, Myron Souris
Published in the Novemeber 17, 2020 edition of the American Go E-Journal.

In this no komi game between low dan players, Yuan Zhou covers examples of the importance of when to play and protect cuts.  But the main focus of the game is how to split and attack White's groups, after White invades Black's upper framework.

Yuan Zhou 7 dan is one of the strongest players in the US.  He has won many titles.  Zhou is also a popular teacher, lecturer, and author.  He lives in Germantown, MD, and can be reached at yuan.zhou@zhouyuan.com .  This commentary is typical for Zhou, who has published several books, including such thorough commentaries of pro games at Slate & Shell (www.slateandshell.com).];
B[pd];W[dc];B[dp];W[pq]
C[By playing a cross-corner opening pattern, Black aims to make more difficult a large territory or moyo for White.];
B[qo]
C[Breaking a corner is a good idea.];
W[op]
C[The famous Honinbo Shusako's kosumi.  Normally in a no komi game, White pincers to start complications, but this kosumi is not a mistake.  The Fine Arts AI program plays this move a lot.];
B[qk]
LB[ce:A]
C[Normally, Black's move is a joseki extension, as in this game.  However, because White's previous move is not a guaranteed sente play, normally Black would play instead to break the top left corner at A, which is better at this point.];
W[ce]
C[A big move and a good choice.];
B[nc]
C[Also correct.];
W[fq]
C[Naturally, White attacks Black's corner, which is the correct direction.];
B[cn];W[dq]
C[A newer idea from the AI programs.];
B[cq]
C[The usual response.];
W[cr];B[eq];W[dr]
C[A joseki nowadays.];
B[ep];W[er];B[bq]
C[Now White has a choice.];
W[fp]
LB[hq:B]
C[This choice is more powerful than B, which defends the bottom area.

Both sides have made no mistakes, all good moves.  Although actually, playing at B would be more useful for White in this case.

The next move is important.]
(;
B[en]
C[Slow.  Playing here is too early.];
W[jp]
C[This exchange is good for White.];
B[fo]
C[Slow and unneeded.  Black should leave the aji around A for possible future use.]
LB[hq:A];
W[hp]
C[Another good trade for White.];
B[oo]
C[A good play on the boundary between moyos.];
W[no];B[on];W[qp]
C[White is happy with this development.];
B[ro];W[np]
TR[qp]
C[Connecting here is slow.  Black cannot cut at this point.  After the kick with the marked stone, White no longer has a potential problem here.];
B[ic]
C[A big move.];
W[re]
C[Correct.  White needs to break the right side area.];
B[qe]
C[The strongest move, aiming for the outside.];
W[rd];B[rf]
C[Correct.];
W[pc]
LB[qf:A]
C[After this move the cutting point at A is the key.  Simply Black connecting at A is now big.];
B[oc]
LB[qf:A]
C[White should now cut at A.];
W[pb]
LB[qf:A]
C[After this extension Black must connect at A, which would make Black very thick.];
B[qd]
C[A bad move.];
W[qf]
C[Cutting here is correct.  Now Black has an incomplete shape.];
B[rc]
C[Black can take the corner, but ...];
W[rg]
C[... this trade is better for White.]
(;
B[sd]
C[Mistake.];
W[sf]
LB[pf:A]
C[Now Black is not going to play A.];
B[qc]
C[White is much better now in the upper right and has sente.];
W[ci]
C[Now White is ahead.];
B[ec]
TR[ic]
LB[fc:A][ee:B]
C[With Black's marked stone in place, White is happy about this contact play.

Black should have played at A instead, aiming for B next.]
(;
W[eb];B[db];W[cb];B[dd]
C[Black is a little bit better here.];
W[cc];B[fb];W[da];B[fd];W[qi]
LB[qh:A]
C[Big, preventing Black A.  The opening is still good for White.];
B[pf]
C[Black needs to expand the top area.];
W[pg];B[og]
C[Black's double hane is correct.]
(;
W[oh];B[ph];W[qg];B[ng]
C[Black is happy to make this extension.];
W[jd]
C[Correct, even though White would like to play on the right.];
B[id]
C[Attacking here is correct.];
W[je]
C[White should jump out one space instead.]
(;
B[ie]
C[Wrong direction.  Not good.];
W[jf];B[hg];W[jh]
C[Now this situation is good for White.  Black's top right moyo is gone.  White is ahead in the game.];
B[cg]
C[Black has to be aggressive.];
W[cl];B[bf]
C[Black tries to for sente, but White's corner is pretty thick.];
W[de];B[ed]
(;
W[cd]
C[Now Black has a monkey jump.];
B[eg];W[ei]
C[White remains ahead, but has 2 groups that are not fully settled:  on the left side and on the center top.  Black must attack those groups to get the game back.

Black needs to make sure these groups do not connect.  If White connects the groups, the game is over.];
B[dj];W[di];B[cj];W[ek];B[bi];W[bh];B[bk]
C[Black is taking away White's base.];
W[ai];B[bj];W[ch];B[ej];W[fj];B[bl]
C[Black is making the game more complicated.]
(;
W[ff]
C[Unnecessary.];
B[fg];W[fi]
C[White has to prevent a cut here.];
B[dg]
C[Black prevents a cut as well.];
W[gf]
C[This move does not work.];
B[gg];W[ee];B[fe]
C[An unneeded bad move.  Instead, Black should prevent White from connecting the 2 groups.];
W[ef];B[hf];W[ge];B[gd]
C[Black manages to stay connected.];
W[he];B[if];W[hd];B[gc]
C[This result is a gain for White.];
W[hc]
LB[jc:A]
C[This push is a bad move that helps Black.  Instead, White should play at A, which is sente.];
B[hb]
C[This move helps Black a lot.]
(;
W[ld]
C[Aiming for more points here is a mistake.];
B[ad]
C[Sente.];
W[ac];B[ae];W[bg]
LB[ii:A]
C[White should still play at A, instead.  White will lose a couple of points in the corner, but connecting the 2 groups is much more important.];
B[cf];W[bd];B[rq]
LB[hi:A]
C[Black should play at A, but instead goes for more points.  Neither player sees how important the situation is with White's 2 unsettled groups.];
W[of];B[nf];W[pe];B[oe];W[pf];B[ne]
LB[me:A]
C[Black should play at A instead.];
W[jb]
C[This peep is good for White.];
B[jc];W[kc];B[ib];W[lb];B[mb]
C[Black prevents a connection to White's 2 stones in the corner and takes away an eye.];
W[fl]
LB[ii:A]
C[White should play at A instead.];
B[hn]
C[Black is out.];
W[rp]
LB[ii:A]
C[White should play at A instead.];
B[sp];W[jn]
C[White keeps missing the critical move.];
B[hj]
C[Finally, Black sees the correct move.];
W[hk];B[ik];W[hl];B[ii]
C[Now Black is attacking both groups.];
W[il]
LB[im:A]
C[This move helps Black.  White should play at A instead.];
B[jk]
C[White's group at the top is in danger.];
W[lh];B[mi]
C[Black clearly sees the possibility now.  This move also makes a gain in the center.];
W[kj];B[qr]
C[A good sente move, but Black should continue in the center.];
W[pr];B[ps];W[os];B[qs];W[qq];B[sr];W[or];B[kk]
C[White is going to have to pay a price now.];
W[lj];B[im];W[jm];B[rj];W[ri]
LB[oi:A]
C[White misses a chance to help the center.  White A instead is good.];
B[go];W[ho];B[gm];W[jl];B[ja]
C[Black ruins a White eye.];
W[kb];B[fa]
C[This move is not really sente.];
W[ea];B[dl]
C[A small move.];
W[mc];B[md];W[nb]
LB[oi:A]
C[White should not risk this ko.
White should fix the center at A instead.];
B[lc];W[gb];B[ga];W[mc];B[ma];W[la]
LB[ob:A]
C[To make a bigger ko, White should connect at A, instead.];
B[lc]
C[Black needs to win this ko.];
W[rs];B[mc]
C[Ending the ko is the correct decision for Black.];
W[rr]
C[White gains 10+ points, but ...];
B[le]
C[... White is in great danger here.];
W[kd];B[ml];W[mj]
C[Actually, now White is dying.  Black is too thick.];
B[ni];W[nj];B[oi]
C[White's top group has no eyes.];
W[oj];B[pi];W[pj];B[qj]
C[Black is reading well.];
W[pl];B[qm];W[nl]
C[White is making an eye.];
B[mm]
C[Finding a 2nd eye is hard for White.];
W[lf];B[li];W[ki];B[kg]
C[The reading here is pretty easy for Black.];
W[jg];B[lg];W[mg];B[mh];W[ll]
C[White's last try.];
B[lk];W[nm];B[nn]
C[White really has no chance.];
W[pm];B[pn];W[ql];B[rl];W[rm];B[qn];W[sl];B[rk];W[pk]
C[Sente, but ...];
B[rn];W[mk]
C[... not enough for White.];
B[mn];W[om]
C[Too obvious.];
B[ok];W[ke]
C[White has no chance.];
B[me];W[hh]
C[White's last try.];
B[ih];W[ig];B[gh]
C[White should not have started the ko, but the bigger mistake was when White did not connect earlier in the center.]
)
    (;
    W[ii]
    C[White needs to play here to connect the 2 groups.]
    )
)
    (;
    W[cf]
    C[White can connect, which is good enough.]
    )
)
    (;
    W[be]
    C[White should block instead.]
    )
)
    (;
    B[jg]
    C[Black should cap here.]
    )
)
    (;
    W[of]
    C[White should atari first.];
    B[pe];W[ph];B[ng]
    C[This result is good for White, who has sente to reduce at the top.]
    )
)
    (;
    W[ed]
    C[White should play on the outside.];
    B[fc];W[db];B[fd];W[ee]
    C[This result is good for White.  Black is overconcentrated with the 2-space extension.]
    )
)
    (;
    B[pf]
    C[Black should force here first.];
    W[qg];B[sd];W[sf];B[qc]
    C[This result is much better for Black than the game.]
    )
)
    (;
    B[gr]
    C[Black should attack this way.];
    W[fr];B[kq]
    )
)

