Tesujis are the most efficient fighting weapons in go. A mastery of tesujis is essential for success at all stages of the game, beginning with the tesujis that lie concealed in josekis and extending to endgame tesujis that may make all the difference in a close game. Whatever your level, studying tesujis will make you stronger, so how about starting with the top ten tesujis?
(;AB[lp]AB[mp]AB[no]AB[oo]AB[po]AB[qo]AW[mo]AW[mn]AW[np]AW[oq]AW[pp]AW[qp]C[Black to play Black has been cut into two, but he can exploit the thinness of White's shape in the corner.]AP[goproblems];B[rp];W[rq];B[qq]
(;W[pq]LB[rp:1]LB[rq:2]LB[qq:3]LB[op:a]LB[mq:b]C[Black hanes at 1, then cuts at 3. This combination is the epitome of tesuji, which is presumably why professionals chose it as number one. The key point is keeping the two ataris at 'a' and 'b' in reserve, waiting to see how White answers in the corner. If White plays 'c', Black 'a' is a double atari.]LB[qr:c];B[nq];W[op];B[qr];W[ro];B[sp];W[so];B[or];W[sq]LB[pq:1]LB[nq:2]LB[op:3]LB[qr:4]LB[ro:5]LB[sp:6]LB[so:7]LB[or:8]LB[sq:9]C[The atari of 1 looks like the only move, but then Black ataries at 2, leading White into shortage of liberties. If 3, Black descends at 4. He next sacrifices a stone with 6, setting up the 'tombstone squeeze'.];B[rp];W[sp];B[pr];W[rp];B[qm]C[Black squeezes, then jumps to 5: White collapses. That means that White answering at Q3 is unreasonable for White. RIGHT]LB[sp:2]LB[pr:3]LB[rp:4]LB[qm:5])
(;W[ro];B[op];W[pq];B[nq]LB[ro:1]LB[op:2]LB[pq:3]LB[nq:4]LB[qr:a]TR[mo]TR[mn]C[White has no choice but to forget about the double atari and capture with 1 or 'a'. Either way, Black captures with 2 and 4, so White's marked cutting stones now look rather foolish. RIGHT]))