(;
GM[1]
SZ[19]
AW[dd][nc][kc][ok][qk][ro][jq][cq][dp][fp]
AB[pd][pc][qi][oi][po][pq][lq][bp][cn][ck]
TR[ro]
C[Problem 9. Black to play.  

White has just slid under Black's corner enclosure with the marked stone. How should Black attack White's position on the right ? ]
(;B[qn]
TE[2]
C[Correct Answer.  

Black 1 and ... ]
;W[rn]
(;B[rm]
C[... 3 stop White from making eyeshape. ]
(;W[rl];B[qm];W[sm]
LB[rq:A][pk:B][rl:4]
C[White links up with 4 and 6, but even if she jumps to A, she doesn't have two eyes yet. Black is also threatening to wedge in with B. <= ]
)
(;W[qm]
TR[rm]
C[Variation.  

When Black blocks with the marked stone, White might cut with 4. But ... ]
;B[ql];W[pm];B[rk];W[pl];B[rl]
C[... Black can link up to his allies above with the sequence to 9. White is now split into two weak groups. <= ]
))
(;B[qm]
LB[rm:@]
C[Failure.  

The hane @ in the Correct Answer is the key move. It is a mistake for Black to extend to 3. ]
;W[rm];B[ql];W[rl];B[rk];W[rj];B[pk];W[qj];B[pj];W[ri]
C[White can live with the sequence to 12 and Black's moyo in the upper right has been erased. <= ]
))
(;B[rq]
C[Failure.  

Black 1 lets White ... ]
;W[qm]
C[... settle her group with 2. White now has nothing to worry about. ]
)
(;B[qp]
C[Failure.  

Black 1 here is also bad. ]
;W[qm]
C[White responds with 2. <= ]
)
)