The following problem came up in natural game play. There are many wrong moves that black can make which will cause him to be devastated, but only one correct move to take the corner.
(;AB[rr]AB[rq]AB[qq]AB[qp]AB[oq]AB[qo]AB[ro]AB[so]AB[sn]AB[mr]AB[or]AB[nr]AB[mq]AB[lq]AB[kq]AW[nm]AW[pq]AW[pr]AW[qr]AW[os]AW[rs]AW[sr]AW[sp]AW[jp]AW[kp]AW[jr]AW[lp]AW[mp]AW[np]AW[nq]AW[op]AW[po]AW[no]AW[nn]AW[mn]AW[on]AW[pn]AW[qn]AW[rn]AW[sm]AW[rl]C[Black to play and live.]SZ[19]AB[pp]CA[Windows-1252]AP[MultiGo:4.4.4]MULTIGOGM[1]
(;B[qs];W[ps];B[ns]C[Correct! Black takes the corner.RIGHT])
(;B[ps];W[qs];B[ns];W[sq]C[Wrong!])
(;B[sq]C[Wrong!])
(;B[rp]C[Wrong!])
(;B[ns];W[sq]C[Wrong!]))