(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
AW[qi][pm][qn][po]AB[oc][qd][qo][qp][nq][pq]C[[Written by Jack Jin, jackjin1988@hotmail.com\]

if w tenuki, b can invade]
;B[qg]
(;W[]C[When white plays tenuki, there are weaknesses in white's base.]
(;B[qk]C[this invasion point is not very good]
;W[pj]
;B[pk]
;W[ok]
;B[ri]
;W[rh]
;B[rj]
;W[qh]
;B[rg]
;W[sh]C[hard for b]
;B[oj]
;W[pl]
(;B[nk]
;W[ol]
;B[ph]
;W[oi]
;B[pi]
;W[qj]
;B[nj]
;W[rk]
;B[pg])
(;B[rl]
;W[oi]
(;B[nj]
;W[rm])
(;B[rn]
;W[nj])))
(;B[rj]C[this is an interesting invasion]
(;W[ri]C[w cant play at s11]
;B[ql]
;W[rm]
;B[qj]C[w has two weak groups, not very good])
(;W[pk]
;B[ri]C[w can simply let b get connection and tenuki]))
(;B[ql]C[this is the most popular invasion point]
;W[rm]C[b has three choices, q10,r10,s10]
(;B[pj]
(;W[qj]
;B[qk]
(;W[pi]C[this is an overplay]
;B[rj]
;W[ri]
;B[ol]C[w has two weak groups])
(;W[rk]
;B[rl]
;W[sl]
;B[rj]
;W[sk]
;B[pi]
;W[ri]
;B[qh]
;W[rh]
;B[rg]
(;W[ol]
;B[sh]
;W[sj]
;B[sg]
;W[si]C[this is joseki, both ok])
(;W[]C[p8 is a very big point, w has to think clearly if tenuki is good]
;B[sh]
;W[sj]
;B[sg]
;W[si]
;B[ol]
(;W[ro]
;B[rp]
;W[sp]
;B[sn]
;W[rn]
(;B[so]
;W[sm]
;B[so])
(;B[rr]C[Black can also play here and it would be painful for white to have to come back and make the 2nd eye.]))
(;W[nn]
;B[so]C[Note that when black jumps here, there is a ko shape left.]
;W[mm]
;B[rn]
;W[qm]
;B[sm]))))
(;W[rk]C[w can also play here]
;B[rl]
(;W[sl]
;B[rj]
;W[qj]
;B[qk]
;W[sk]
;B[pi]C[it is the same])
(;W[qk]
;B[pl]
;W[sl]
;B[om]C[this is not good for w])))
(;B[qj]
;W[pj]
;B[pk]
;W[rj]
;B[rk]C[if b has more big ko threats, making a ko is quite severe])
(;B[rj]
;W[pk]
(;B[qj]C[pushing is not very good]
;W[pj]
;B[pi]
;W[oi]
;B[ph]
;W[qk])
(;B[pj]
;W[qj]
;B[qk]
(;W[ok]
;B[ri]
;W[op]
;B[oq]
;W[qh]
(;B[rh]
;W[oi]C[this is joseki])
(;B[ph]C[b cant do this]
;W[pi]
;B[oi]
;W[rh]
;B[rg]
(;W[sh]C[but if w tries to kill b, w will be in trap]
;B[ol]
;W[pl]
;B[oj]C[game over])
(;W[oj]C[w just needs to take the stone]
;B[sh]
;W[pj]
;B[oh]C[it is ok for w
it is w sente and w cant be attacked])))
(;W[pl]C[it is possible for w to consider q8]
;B[ri]
;W[qh]
;B[rh]
;W[oj]
;B[pi]
;W[ph]
;B[oi]
;W[pg]
;B[pf]
;W[ni]
;B[oh]
;W[og]
;B[nh]
;W[of]
;B[nj]
;W[qf]
;B[rg]
;W[pe]
;B[rf]
;W[mf]C[this is a complex fight])))))
(;W[oi]C[Normally white comes back to defend.]))
