(;
GM[1]
SZ[19]
AW[fc][jd][nc][ql]
AB[pj][dj][dp][pd][pp][dd][pf][df][jp][jj]
LB[ql:7][jp:6][jd:5][nc:1][fc:3][df:4][pf:2]
C[Problem 43. Black to play.  

White invades the right side with 7. How should Black deal with this invasion ? ]
(;B[qn]
TE[2]
C[Correct Answer.  

The pincer of Black 1 is the standard move in this kind of position (see Problem 16). ]
(;W[ol]
C[White's stones are without a base, so she must escape into the center with 2. <= ]
)
(;W[rj]
C[If White 2 here, ... ]
;B[pl]
C[... Black will attach at 3 and build influence in the center. <= ]
))
(;B[qj]
C[Variation.  

Playing Black 1 is a bit weak. ]
;W[qc]
C[White might treat her stone in the lower right lightly and invade the upper right corner with 2. ]
;B[pc]
C[After 3, ... ]
;W[pb];B[qd]
C[... it is important that Black takes sente by turning at 5 ... ]
;W[rb];B[rc]
C[... and playing atari with 7. This secures Black a lot of territory in the upper right side and ... ]
;W[qb];B[qn]
C[... he can also secure territory below with 9. See Problem 47 for the continuation of this game. <= ]
)
)