(;
GM[1]
SZ[19]
AW[db][fc][hd][jd][lc][qf][pf][pj]
AB[cc][dd][cf][nc][nd][pd][qe]
C[Problem 148. White to play.  

Black's formation is very tight. Is it possible for White to invade here ? ]
;W[qc]
TE[2]
C[Correct Answer.  

White's invasion at 1 is unreasonable. ]
;B[re]
C[Black blocks at 2 and ... ]
;W[ob];B[nb]
(;W[oc];B[od];W[rb];B[oa];W[pb];B[sc]
C[... after Black 10 it is clear that White is dead. <= ]
)
(;W[pb]
C[Variation.  

If White draws back with 5, ... ]
;B[sb]
C[... Black's killing move is at 6. From this diagram it is easy to see just how big Black's territory is. <= ]
)
)