(;AW[rq]AW[qq]AW[pq]AW[oq]AW[np]AB[oo]AB[op]AB[pp]AB[qp]AB[rp]AB[ro]AW[qn]AW[rn]AW[ql]AW[pl]AW[qm]AW[sm]AW[rk]AW[no]AW[nn]AB[om]AB[pm]AB[nm]AW[rj]AW[sl]AB[sj]AB[ri]AB[rh]AW[qi]AB[pj]AW[qj]AB[pk]AB[ok]AB[ph]AB[qh]AB[pi]MA[pl]MA[ql]MA[qm]MA[qn]MA[rn]MA[sm]MA[sl]MA[rk]MA[rj]MA[qj]MA[qi]C[Can White do anything with the marked group? If not, play T for tenuki.]AW[ol]AB[ml]AB[mn]AW[nl]AB[nk]AB[mk]LB[ni:T]MA[nl]MA[ol]AP[goproblems] (;W[on];B[pn] (;W[po];B[qo] (;W[so];B[sp];W[sq];B[sn]C[A ko! White has a local ko threat at N7 so Black can take first. (thanks MeleeNewb)RIGHT]) (;W[sp];B[so];W[sn];B[sq])) (;W[so];B[sp] (;W[po];B[qo];W[sq];B[sn]C[A ko! White has a local ko threat at N7 so Black can take first. (thanks MeleeNewb)RIGHT]) (;W[qo];B[po])) (;W[qo];B[po];W[so];B[sp]) (;W[sp];B[so];W[po];B[qo];W[sn];B[sq])) (;W[so];B[sp]C[Black offers the strongest resistance.] (;W[on];B[pn] (;W[po];B[qo];W[sq];B[sn]C[A ko! White has a local ko threat at N7 so Black can take first. (thanks MeleeNewb)RIGHT]) (;W[qo];B[po])) (;W[pn];B[on])) (;W[ni]C[Nope. White can do something.]) (;W[pn];B[on]) (;W[sp];B[so];W[on];B[pn];W[po];B[qo];W[sn];B[sq]) (;W[po];B[on]))