(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
PB[Black to play]AW[bq][ar][cr][dr][er][fr]AB[ap][bp][cq][dq][eq][fq][hq][gr][gs]C[This is the problem position. Black to play.]
;B[bs]C[This is the vital point - this is the correct way to kill white.]
(;W[br]C[Connecting leaves too little space on the edge.]
;B[fs]
;W[es]
;B[cs])
(;W[cs]C[This looks like the strongest response.]
;B[br]C[But black can play the 2-2 point tesuji.]
(;W[aq]C[This is self-atari]
;B[as])
(;W[as]
;B[br]C[White still cannot connect the single stone
because of damezumari.]
;W[bs]
;B[aq]C[White dies.]))
(;W[fs]C[And widening the basis clearly goes nowhere.]
;B[br]))
