(;
GM[1]
SZ[19]
AW[lc][pc][qe][cf][df][ci]
AB[dd][ce][fd][jc]
C[Problem 84. Black to play.  

White's three-space extension from her corner enclosure is ideal. However, Black has a strong position on the left. How should Black invade ? ]
(;B[nc]
TE[2]
C[Correct Answer.  

Black should invade at 1. ]
;W[le]
C[If White jumps out with 2, ... ]
;B[ne]
C[... Black escapes into the center with 3. <= ]
)
(;B[oc]
C[Failure.  

Attaching with 1 ... ]
;W[pd];B[pb];W[qb];B[md];W[ld];B[me]
LB[md:5]
C[... and trying to escape with 5 and 7 is not good. ]
;W[mc]
LB[ld:6]
C[Black's shape is destroyed when White plays 6 and 8. <= ]
)
)