While playing a game on KGS, my opponent forgot to defend a weakness on his border. Make black regret he didn't enforce this border (should be easy ;-) ) [The southern part of the black group was changed to make it obvious that the black group was already alive and the position, which took place in the center, moved to the side for convenience]
(;AP[goproblems]AB[js]AB[jr]AB[jq]AB[ip]AB[io]AB[jo]AB[kn]AB[ln]AB[mn]AB[no]AB[np]AB[nq]AB[nr]AB[ns]AB[kr]AB[mr]AB[lr]AW[is]AW[ir]AW[iq]AW[hq]AW[hp]AW[ho]AW[in]AW[jn]AW[km]AW[lm]AB[mm]AB[nm]AW[ml]AW[nl]AW[ol]AW[om]AW[nn]AW[on]AW[oo]AW[op]AW[oq]AW[or]AW[os]TR[kn]TR[ln]TR[mn]TR[jo]TR[io]TR[ip]C[White to play and reduce black](;W[ko](;B[lo](;W[jp];B[kp](;W[jo]C[RIGHT])(;W[lp];B[jo]C[A ko is not what you want here. Black is almost safe from any loss now.])(;W[io];B[jo]TR[jp]C[Don't give black a ko which moreover threatens the white stone at K4.]))(;W[mo];B[kp]C[Black is safe now])(;W[lp];B[kp])(;W[kp];B[jp]))(;B[jp](;W[mo];B[mp](;W[lo];B[kp];W[lp];B[lq]C[Black suffers a great lossRIGHT])(;W[lp](;B[lo]C[];W[mo]C[Snapback, terrible for blackRIGHT])(;B[kp];W[lo];B[lq]C[Black suffers a great lossRIGHT])))(;W[lo];B[mo])(;W[lp];B[mo])(;W[mp];B[mo])(;W[kp];B[mo]))(;B[lp]C[CHOICE](;W[lo];B[mo](;W[jp];B[kp];W[jo]C[A nice little reduction. However white lost the sente.RIGHT])(;W[kp];B[jp]C[That would be too greedy]))(;W[jp];B[kp]LB[hl:T]C[Play T if you want to tenuki](;W[lo];B[mo];W[jo]C[A nice little reductionRIGHT])(;W[hl]MA[lo]C[A nice little reduction. White kept the sente and M5 can now be saved as a ko threat.RIGHT]))(;W[mo];B[lo];W[jp];B[kp];W[jo]C[Black is reducted, though not as much as possible. See variations for details.RIGHT])(;W[kp];B[jp])(;W[kq];B[jp])))(;W[jp];B[kp])(;W[mo];B[ko]C[Black is safe now.])(;W[kp];B[ko]C[Black is safe now. He can connect his groups at N5 or K4.]))