(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
PB[Black to play and live]AW[ko][qo][lp][mp][op][pp][kq][qq][kr][qr]AB[lq][pq][lr][pr][ls][ps]C[This is a problem from the Nihon Ki-in hanky.]
(;B[oq]
;W[nr]
;B[nq]
;W[mr]
;B[mq]C[Blocking at the top is clearly no good])
(;B[nq]C[Likewise this move at the top is no good]
;W[oq]
;B[or]
;W[mq]
;B[mr]
;W[ns])
(;B[nr]C[This move looks interesting]
(;W[nq]C[If white here black can live]
;B[ns])
(;W[oq]C[So white must play here]
;B[or]
;W[mq]
;B[mr]
;W[ns]))
(;B[ns]C[This is the only way to live - the proverb is
play at the centre of symmetry, but this time 
it is also playing on the edge which is unusual.]
(;W[oq]
;B[or]
;W[mq]
;B[mr]C[White's pushes don't work - black already
has the key point for eyes])
(;W[nq]
;B[nr]C[That way black simply lives])
(;W[nr]
;B[nq]C[If white plays this way the black clamp captures the stone
making easy eyes.]
;W[oq]
;B[or]
;W[mq]
;B[mr])))
