(;GM[1]FF[4]ST[2]RU[Japanese]AB[qk][cm][qn][dp][rp][dq]AW[fo][jp][pp][fq][nq][qq]
PL[B]CR[fo]LB[gp:A]C[Question\:

Hi

In that game I was white, here I simply reproduced the situation at the lower side.

My opponent started the invasion at A. 

How should I deal with such an invasion and did black play it correctly?


Thank you]
AP[CGoban:2]SZ[19]CA[UTF-8]DT[2006-02-15]KM[0]MULTIGOGM[1]

(;B[gp]CR[gp];W[fp]CR[fp]C[B's peep at g4 first strengthens w, not good.];B[kq]
CR[kq]
(;W[kp]CR[kp];B[mr]CR[mr];W[nr]CR[nr];B[mq]CR[mq];W[mp]CR[mp];B[hr]CR[hr];W[gr]
CR[gr]
(;B[hp]CR[hp];W[ir]CR[ir]C[W j2 is a good move!];B[iq]CR[iq];W[hs]CR[hs]
(;B[hn]CR[hn];W[jq]C[After w k3, b didn't get anything but a weak group and w didn't lose any point!])
(;B[jq]C[B can't connect...];W[hn];B[io];W[ip];B[hq];W[ho];B[lp];W[lo];B[lq];W[ko]
C[B dies.]))
(;B[jq]C[B should make life at k3.];W[iq];B[ir];W[hq];B[lp];W[lo];B[lq];W[mo];B[kr]
C[B is alive.]))
(;W[jq]C[W should block b if w wants to keep attacking.];B[kp];W[ko];B[mp];W[mq]
;B[lo];W[lq];B[kn];W[jo];B[lp];W[kr]C[Even though b can escape with l3 and l4, b's shape is so ugly and heavy. W gains many points and is much stronger now.]
;B[lm];W[mn];B[ln];W[pl];B[ql];W[pn];B[qo];W[im]C[Still, w can keep attacking like this way.]))
(;B[hq];W[gp];B[lq]C[This is the correct order to invade w's territory, because on both the left side and the right side w has an invasion point. B should first play a move on the left side; when w sorrounds b, b can invade the other side. The stone b just played on the left side can then help him make an eye shape.]
(;W[lp]C[If w surrounds b...];B[kp];W[ko];B[kq];W[mp];B[jq];W[ip];B[gr];W[fr];B[mr]
C[B is alive.]
(;W[ir];B[iq];W[hr];B[gq];W[gs];B[hs];W[is];B[jr];W[fs];B[js];W[hs];B[nr];W[or]
;B[ls])
(;W[nr];B[iq]C[\:)]))
(;W[jq];B[mp]C[B can run if w simply separates b at k3.])))