(;
GM[1]
SZ[19]
AW[fc][cj][dm][cn][co]
AB[dp][pd][pp][dd][cp][dn][en][fp]
LB[fc:9][fp:8][en:6][dn:2][cp:4][cn:1][dm:3][co:5][cj:7]
C[Problem 105. Black to play.  

After White extended to 7, Black defended tightly with 8. White then approached the black stone at the top with 9. How should Black respond ? ]
(;B[jc]
TE[2]
C[Correct Answer.  

Black should not play in the area of White's strength on the left side. Instead, he should pincer with 1 and ... ]
;W[cf]
C[... wait for White to make a second approach move at 2. ]
;B[df]
C[Since Black is weak, he should attach at 3, making his stones strong. ]
;W[dg];B[ce];W[ef];B[de];W[cg]
C[If White connects at 8, ... ]
;B[db]
C[... Black defends the corner with 9. Black's stones are secure, so ... ]
;W[fe]
C[... he doesn't mind being confined by White 10 - ... ]
;B[nd]
C[... he maps out territory in the top right with 11. <= ]
)
(;B[cg]
C[How the game continued.  

Black 1 was exactly the move White was hoping for. ]
;W[cc]
C[White wrested the corner from Black ... ]
;B[dc];W[cd];B[de];W[ce]
(;B[cf];W[db];B[eb];W[cb]
C[... with the sequence to 10, ... ]
;B[ec];W[fe]
C[... then neutralised Black's thickness by jumping to 12. This was a very bad result for Black. <= ]
)
(;B[cb]
LB[ce:6]
C[Variation.  

After White 6, Black should have haned with 7 ... ]
;W[bb];B[db]
C[... and connected with 9. ]
;W[cf];B[df];W[bg];B[bh];W[ch];B[dg]
C[With the sequence to 15, Black is thick in the center. ]
;W[bi];B[bc]
C[After exchanging 17 ... ]
;W[bd]
C[... for 18, ... ]
;B[hc]
C[... Black can pincer with 19. ]
;W[fe]
C[If White 20, ... ]
;B[he]
C[... Black plays 21. ]
;W[fg]
C[If White then plays 22, ... ]
(;B[fb]
C[... Black can link up his stones by attaching with 23. <= ]
)
(;B[ab]
C[Even if Black's stones get cut off, they can live by starting a ko ... ]
;W[ba];B[bf];W[ag];B[ad]
C[... with the sequence to 27. <= ]
)))
)