(;GM[1]FF[4]AP[Drago:4.12]SZ[19]CA[UTF-8]AB[jc][pd][qi][qp][oq][oo][fp][jp]AW[dc][de][dn][cq][qk][qn][ok]C[Black's moyo at the bottom is quite strong, but his moyo in the top right is still rather thin. How should black attack it?]
(;W[ke]C[Correct.
White must first play 1, ...];B[ld]C[... forcing Black to defend with 2.];W[qc]C[He then invades with 3.];B[pc];W[qd];B[qe];W[re]
(;B[rf];W[qf];B[pe];W[rg]
(;B[pf];W[sf];B[qg];W[rf]
;B[oi]C[After 16, White has secured the corner and Black is overconcentrated at the top.])
(;B[rd]C[Bad for Black.
Black 12 in the correct answer is an important point. If Black takes the corner with 12 and ...];W[sf]
;B[rc]C[... and 14 instead, ...];W[pf]TR[qi]C[... White pushes up with 15 and the marked stone is isolated.]))
(;B[qf]C[Variation
Instead of 8 in the correct answer, Black might extend as here. ...];W[rf];B[qg];W[pb];B[ob];W[qb]
;B[nc]TR[ld][ke]C[The sequence up to 14 can be expected, but the exchange of the marked stones has caused Black to be seriously overconcentrated.]))
(;W[qc]C[Wrong order of moves.
White must not rush to invade with 1. ...];B[pc];W[qd];B[qe];W[re];B[rf];W[qf];B[pe];W[rg];B[pf];W[sf]
;B[qg];W[rf];B[oi]
;W[ke]L[ld]C[After the sequence to 14, Black will not answer 15 with A. Instead ...];B[je]C[he will attach with 16 and use his thickness on the right to attack White's stones.];W[jf]
;B[ie]L[ld]))