(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
PB[Black to play]C[Just play through the moves to move 20 which is the problem position. These do not represent a game sequence!]
;B[pr]
;W[qr]
;B[ps]
;W[rr]
;B[qq]
;W[pq]
;B[rq]
;W[pp]
;B[rp]
;W[qp]
;B[ro]
;W[sq]
;B[oq]
;W[pn]
;B[op]
;W[qn]
;B[oo]
;W[rn]
;B[nr]
;W[sn]C[This is the problem position. Black to play.]
(;B[qo]
;W[po]C[Black clearly cannot connect through the bamboo
joint he will have to capture the corner stones.])
(;B[sp]
;W[sr]
;B[qs]
;W[qo]C[This way clearly loses the capturing race.])
(;B[qs]
;W[sr]
(;B[rs]
;W[sp]
(;B[ss]
;W[so]C[This way white either links up or captures faster.])
(;B[so]
;W[qo]))
(;B[sp]
;W[qo]
;B[rs]
;W[so]))
(;B[rs]C[This is sometimes a tesuji as white cannot
seperate it from the stones to the left.]
(;W[sp]C[Is this move fast enough?]
(;B[qs]
;W[sr]C[This follow up fails])
(;B[sr]C[So try the throw in]
;W[ss]
;B[qs]C[No: white is caught short of liberties]))
(;W[sr]C[However white can connect here.]
(;B[sp]
;W[qo])
(;B[qs]
;W[sp]C[White either connects out or captures])))
(;B[sr]C[This is correct. The throw-in works, however, as a first move.]
(;W[ss]
;B[qs]
;W[sp]
;B[rs]C[White runs out of liberties.])
(;W[sp]
;B[rs]
;W[ss]
;B[qs]C[White is still out of liberties.])))
