(;AW[rj]AW[pq]AW[qo]AB[po]AB[pn]AW[qm]AW[ql]AB[qk]AB[pk]AB[pl]AB[pm]AW[rk]AB[oq]AB[or]AB[op]AB[ps]AW[pr]AW[qq]AB[pp]AW[qp]AB[os]TR[ps]C[Black has just played the marked stone. How should white respond?]AP[goproblems] (;W[rr]C[Good! Since R1 is not safe, this is the best response. RIGHT]) (;W[qs];B[qn];W[rn];B[rr] (;W[rq];B[qr]C[: (]) (;W[qr];B[rm] (;W[ro];B[rl]) (;W[rl];B[ro] (;W[rp];B[sn]) (;W[sm];B[rp])))) (;W[qr];B[rr] (;W[rs];B[qs]) (;W[qs];B[qn];W[rn];B[rm] (;W[ro];B[rl]) (;W[rl];B[ro] (;W[rp];B[sn]) (;W[sm];B[rp])))))