(;
GM[1]
SZ[19]
AW[dd][dp][jp][mp][qi][qf][pf]
AB[pq][pk][rj][qe][pd][nd][jd]
LB[mp:1]
C[Problem 86. Black to play.  

Suppose White doesn't defend her stones in the upper right and extends to 1 at the bottom instead. How should Black continue ? ]
(;B[oi]
TE[2]
C[Correct Answer.  

The cap of Black 1 keeps up the pressure on White. ]
;W[ri];B[qj];W[pi];B[oj];W[oh];B[nh];W[og]
C[After White 8, ... ]
;B[op]
C[... Black can defend his territory in the lower right with 9. <= ]
)
(;B[op]
TE[2]
C[Correct Answer.  

It is also possible for Black to simply defend with the diagonal move of 1 and wait to see how White will play at the top. <= ]
)
)