(;
GM[1]
SZ[19]
AW[cb][dc][eb][ed][jd][jc][kc][jf][qf][qk][qn][dq][eq][cp][cn][cj]
AB[cc][cd][ce][kd][ld][lf][mc][qd][pd][qp][pq][jp][ch][ep][fp][fq]
TR[jf]
C[Problem 109. Black to play.  

White has jumped into the center with the marked stone. What should Black do ? ]
;B[qi]
TE[2]
C[Correct Answer.  

Black is strong above and below, so he can invade White's thin position with 1. ]
;W[ph];B[pi];W[nh];B[oi];W[oh];B[lh];W[ni]
C[If White plays the sequence to 8, ... ]
;B[pk]
C[... Black leans on the white stone below with 9. Next ... ]
;W[pl]
TR[pk]
C[... White answers the marked stone with 10. ]
;B[ok];W[mj];B[ol];W[pm];B[rk];W[rl];B[qj];W[ql];B[ml];W[kj];B[ro];W[rj];B[ri];W[sk];B[oo];W[rn]
C[When White plays 26, her stones are alive, but Black has built up a moyo at the bottom. ]
;B[jg]
C[After 27, White's stones are still insecure. <= ]
)
)