(;
GM[1]
SZ[19]
AW[jc][lb][mc][nc][nb]
AB[dd][hc][kb][mb][lc][pd][pf]
LB[mc:2][kb:3][mb:1][nb:4][qc:B][ld:A]
C[Problem 16. Black to play.  

The moves to 3 are normal, but instead of A, White ataries with 4, aiming to invade the corner at B. How should Black answer ?  

<See Reference Diagram 16 for White 4 at A.> ]
;B[pb]
TE[2]
C[Correct Answer.  

Defending the corner with 1 is best. ]
;W[kc]
C[White next plays 2 and ... ]
;B[la];W[ld];B[jb];W[lb];B[ic]
C[... the moves to 7 are natural. Black has no reason to be dissatisfied. <= ]
)
)