(;GM[1]FF[4]CA[UTF-8] SZ[19]RU[Japanese]KM[0]TM[1800,0,30,5]PW[]PB[]PL[B]AE[qo]AW[qp][mq]AB[oq][po]AW[pp]LB[qp:1][oq:2][mq:3][po:4][pp:5]C[let's walk through this joseki variation] ;B[op]CR[op] ;W[oo]CR[oo]LB[no:A]C[play at A] (;B[no]CR[no] ;W[on]CR[on] (;B[mp]CR[mp] ;W[lp]CR[lp] (;B[lo]CR[lo] ;W[kp]CR[kp]C[keep going?] ;B[ko]CR[ko] ;W[jp]CR[jp]C[black must now hit the vital spot] ;B[ro]CR[ro] ;W[qr]CR[qr]LB[pr:A][qo:B]C[A or B?] (;B[qo]CR[qo] ;W[or]CR[or]C[let's play a good forcing move along the bottom now] (;B[pq]CR[pq] ;W[qq]CR[qq] (;B[pr]CR[pr] ;W[nq]CR[nq] (;B[np]CR[np] ;W[ps]CR[ps]C[let's take our forcing moves along the bottom now] ;B[nr]CR[nr] ;W[os]CR[os]LB[mr:A]C[play at A] ;B[mr]CR[mr] ;W[lq]CR[lq] (;B[nn]CR[nn] ;W[om]CR[om]C[this move is necessary to stop white's shape-hurting atari] ;B[rq]CR[rq]C[RIGHT the correct tesuji for the corner. reason why to follow.]) (;B[rq]CR[rq] ;W[nn]CR[nn] ;B[mo]CR[mo]C[too painful]) (;B[ql]CR[ql] ;W[nn]CR[nn]) (;B[qk]CR[qk] ;W[nn]CR[nn])) (;B[nr]CR[nr] ;W[np]CR[np] ;B[os]CR[os] ;W[mr]CR[mr]C[black is toast. the ko is unwinnable])) (;B[nr]CR[nr] ;W[nq]CR[nq] (;B[np]CR[np] ;W[pr]CR[pr]C[white's shape is better than it should be in this variation]) (;B[pr]CR[pr] ;W[np]CR[np] ;B[os]CR[os] ;W[mr]CR[mr]C[black is dead]))) (;B[nr]CR[nr] ;W[nq]CR[nq] (;B[np]CR[np] ;W[pq]CR[pq]C[too good for white]) (;B[pr]CR[pr] ;W[np]CR[np] ;B[os]CR[os] ;W[pq]CR[pq] ;B[or]CR[or] ;W[mr]CR[mr]C[black toast])) (;B[nq]CR[nq] ;W[nr]CR[nr]C[bad shape]) (;B[pr]CR[pr] ;W[nq]CR[nq] (;B[np]CR[np] ;W[pq]CR[pq]) (;B[nr]CR[nr] ;W[np]CR[np] (;B[pq]CR[pq] ;W[qq]CR[qq] ;B[os]CR[os] ;W[mr]CR[mr]) (;B[os]CR[os] ;W[pq]CR[pq] ;B[or]CR[or] ;W[mr]CR[mr])))) (;B[pr]CR[pr] ;W[rp]CR[rp] ;B[qo]CR[qo] ;W[qm]CR[qm])) (;B[lq]CR[lq]C[too strong])) (;B[nn]CR[nn] ;W[pn]CR[pn]C[this helps white fix his shape])) (;B[mp]CR[mp] ;W[no]CR[no] (;B[pn]CR[pn] ;W[np]CR[np]) (;B[np]CR[np] ;W[pn]CR[pn]C[good for white])) (;B[qo]CR[qo] ;W[ro]CR[ro] ;B[rn]CR[rn] ;W[rp]CR[rp]C[this fight is good for white]))