(;
GM[1]
SZ[19]
AW[dd][fd][kc][nc][pb][ph][qm][qp][oq]
AB[qc][pd][pf][qk][ok][dp][dj][cf]
TR[ph]
C[Problem 49. Black to play.  

The marked white stone has a lot of room to maneuver. How should Black attack ? ]
(;B[oi]
TE[2]
C[Correct Answer.  

The shoulder hit of Black 1 is severe. ]
;W[oh]
C[If White 2, ... ]
;B[nh]
C[... Black presses with 3 and ... ]
;W[og]
C[... White has to turn at 4. ]
;B[nd]
C[Black now leans on White's stones above with 5. ]
(;W[ng]
LB[nd:5]
C[White might want to ignore Black 5 and turn at 6. ]
;B[mc]
C[Black would the play 7 ... ]
(;W[mb];B[md];W[nb]
C[If White defends upon to 10, ... ]
;B[mg];W[mh];B[ni];W[mf];B[lg];W[nf];B[lf]
C[... Black traps White's stones on the right with the sequence to 17. <= ]
)
(;W[lg];B[md]
C[... and 9, taking a large profit at the top. Black is satisfied with this result. <= ]
))
(;W[md]
C[If White defends the top with 6, ... ]
;B[me]
C[... Black keeps up the pressure with 7. ]
(;W[ld]
C[After White 8, ... ]
;B[ng]
C[... Black turns at 9 and the white stones on the right are trapped. <= ]
)
(;W[ne]
C[If White plays at 8 here, ... ]
;B[nf]
C[... Black ataris at 9 here. The white stones on the right are trapped. ]
)))
(;B[nh]
C[Failure.  

Capping with Black 1 doesn't work ... ]
;W[pj]
C[... because White will peep with 2. ]
;B[pk];W[ni];B[oi];W[oh];B[mi];W[ng];B[nj];W[of]
C[White now extricates her stones with the sequence to 10. White's stones are safe, but the three black stones in the upper right corner are in trouble. <= ]
)
(;B[ng]
C[Failure.  

Attacking from above with Black 1 ... ]
;W[nh];B[mh]
C[... and 3 is out of the question. ]
;W[ni];B[mg];W[mi];B[li];W[lj];B[ki];W[mk]
TR[qk][ok]
C[After White 10, the two marked stones are isolated and without a base. <= ]
)
)