(;GM[1]FF[4]CA[UTF-8] SZ[19]RU[Japanese]KM[0]TM[1800,0,30,5]PW[]PB[]AB[cp][pp]AW[ep]AB[eq]AW[fq]AB[dq]AW[gp]AB[cn]AW[kq]AB[mq]AE[iq]AW[gr]AB[hq][jp]PL[W]LB[hq:1][gr:2][jp:3]C[black has invaded at 1 through 3. how to respond?] (;W[jq]CR[jq] ;B[iq]CR[iq] (;W[ir]CR[ir] ;B[hr]CR[hr] (;W[hs]CR[hs] ;B[jr]CR[jr] ;W[is]CR[is] ;B[kp]CR[kp] (;W[kr]CR[kr] ;B[lq]CR[lq] (;W[lr]CR[lr] ;B[mr]CR[mr]C[and to finish...] ;W[ho]CR[ho]C[RIGHT the only sequence]) (;W[ho]CR[ho] ;B[lr]CR[lr] ;W[js]CR[js]C[too bad to let black get this sente]) (;W[ip]CR[ip] ;B[lr]CR[lr])) (;W[lq]CR[lq] ;B[lp]CR[lp] ;W[lr]CR[lr] ;B[mr]CR[mr]C[bad for white]) (;W[lr]CR[lr] ;B[lq]CR[lq] ;W[kr]CR[kr] ;B[mr]CR[mr] ;W[ho]CR[ho]C[RIGHT])) (;W[js]CR[js] ;B[hs]CR[hs]C[cannot let black split white like this])) (;W[kp]CR[kp] ;B[jr]CR[jr]C[now white cannot connect underneath]) (;W[lp]CR[lp] ;B[jr]CR[jr]C[now white cannot connect underneath]) (;W[ip]CR[ip] ;B[jr]CR[jr] (;W[hp]CR[hp] ;B[kr]CR[kr]) (;W[kr]CR[kr] ;B[hp]CR[hp]C[now white cannot connect underneath]))) (;W[kp]CR[kp] ;B[jq]CR[jq] (;W[jr]CR[jr] ;B[ir]CR[ir]C[white split]) (;W[jo]CR[jo] ;B[kr]CR[kr] ;W[lr]CR[lr] ;B[jr]CR[jr] ;W[lq]CR[lq] ;B[ko]CR[ko]C[white split])) (;W[lp]CR[lp] ;B[jq]CR[jq]C[white split]) (;W[jr]CR[jr] ;B[hr]CR[hr]C[white split]) (;W[ir]CR[ir]C[too low]) (;W[ip]CR[ip] ;B[iq]CR[iq] ;W[jq]CR[jq] ;B[hp]CR[hp] (;W[io]CR[io] ;B[ho]CR[ho]) (;W[ir]CR[ir] ;B[hr]CR[hr] ;W[hs]CR[hs] ;B[jr]CR[jr] ;W[is]CR[is] ;B[kr]CR[kr] ;W[lr]CR[lr] ;B[lq]CR[lq] ;W[kp]CR[kp] ;B[mr]CR[mr] ;W[jo]CR[jo] ;B[ho]CR[ho]C[white is split])) (;W[iq]CR[iq] ;B[jq]CR[jq] (;W[ir]CR[ir] ;B[jr]CR[jr]C[good for black]) (;W[jr]CR[jr] ;B[ir]CR[ir] ;W[ip]CR[ip] ;B[kr]CR[kr]C[good for black])))