(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
AW[dc][hc][lc][rd][ce][qf][qi]AB[jc][qc][nd][pd]SQ[lc]C[[Written by Jack Jin, jackjin1988@hotmail.com\]

This is a very common invasion]
(;B[ld]C[if b really wants a sente, it is considerable
but locally it is not a good choice]
(;W[mc]C[if w extends to this side, w will be in trouble]
;B[kd]
;W[jb]
;B[kb]
;W[kc]
;B[ib]
;W[md]
;B[me]C[Good for black])
(;W[kc]C[l17 is the correct choice for w, in the following two variations, both good for w locally]
;B[kd]
;W[jb]
(;B[jd]
;W[ic])
(;B[mc]
;W[jd]
;B[je]
;W[id])))
(;B[je]
;W[le]C[this fight is good for w in most cases])
(;B[kd]C[so kosumi is the most common answer]
;W[ld]
;B[le]
;W[jb]
;B[ib]
;W[kb]
;B[ic]
;W[hb]C[b has several choices now]
(;B[me]
;W[ia]
;B[hd]
;W[gd]
;B[he]C[who is better depends on how much b can get in the center])
(;B[ja]C[hane at k19 is not good]
;W[me]
;B[md]
;W[ke]
;B[lf]
;W[jd])
(;B[ha]
;W[me]
;B[lf]
;W[md]
;B[nc]
;W[mf]
;B[lg]
;W[of]
;B[hd]
;W[rc]C[this variation looks good for w, too])
(;B[ia]C[this is the strongest choice]
(;W[me]
;B[md]
;W[ke]
;B[lf]
;W[je]
;B[id]C[w cant cover b])
(;W[ke]
(;B[md]
;W[lf]
;B[me]
;W[id]
;B[je]
;W[jd]
;B[kc]
;W[kf]
;B[lb]
;W[hd]C[very hard to say who's better, w gets much influnce but it is b's sente])
(;B[je]
;W[me]
;B[kf]
;W[lf]
;B[pf]C[very complex fight, hard for both]))
(;W[nb]
;B[me]
;W[pb]
;B[hd]C[b is satisfied, but if there's no big use of b wall, it is also acceptable for w]))))