(;
GM[1]
SZ[19]
AW[cc][dd][fd][kc][nc][pb][jp][dp][fp]
AB[qc][pd][pf][qk][pq][lp][cn][bd][cf][ci]
LB[lp:1]
C[Problem 163. White to play.  

Black has played 1, expanding the moyo he has made from the Chinese Opening and defying White to invade. How should White attack ? ]
(;W[ok]
TE[2]
C[Correct Answer.  

Lightly capping with White 1 is the correct strategy. It flattens Black's moyo ... ]
;B[pm]
C[... since he must answer at 2. There is still aji left in the corner. <= ]
)
(;W[po]
C[Failure.  

White 1 leaves something to be desired. ]
;B[qp]
C[After Black 2, White must worry about being attacked. ]
(;W[ok]
C[If White now caps at 3, ... ]
;B[ol]
C[... Black attaches at 4. ]
;W[nl];B[pl];W[nk];B[nm];W[mm];B[mn]
LB[po:1]
C[After the sequence to Black 10, White 1 has become a wasted move. <= ]
)
(;W[bp]
C[Failure.  

Locally, White 1 is an excellent move, but one of the strategic principles of Go is 'never let your opponent perfect his moyo.' ]
;B[ok]
C[This is exactly what Black does when he jumps to 2. Black's moyo is now very large and solid and Black has taken a commanding lead. <= ]
)
(;W[pm]
C[If White jumps to 3 here, ... ]
;B[ok]
C[... Black jumps to 4, making a moyo at the top and leaving the two white stones below under attack. <= ]
))
)