(;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 37 which is the problem position. These do not represent a game sequence!]
;B[bq]
;W[bo]
;B[bp]
;W[ao]
;B[cq]
;W[co]
;B[dq]
;W[cp]
;B[bn]
;W[dn]
;B[cn]
;W[cm]
;B[bm]
;W[cl]
;B[bl]
;W[dp]
;B[en]
;W[eq]
;B[er]
;W[ep]
;B[fq]
;W[fp]
;B[fr]
;W[gp]
;B[gq]
;W[hp]
;B[gr]
;W[ip]
;B[hq]
;W[iq]
;B[jq]
;W[hr]
;B[]
;W[jr]
;B[]
;W[gs]
;B[]C[Start postition: White to play

The issue in question is the corner.]
;W[fs]
;B[ds]
;W[bs]C[White pushes in and then tries the tricky move of 40.]
;B[br]
;W[ap]
(;B[cs]
;W[dr]
;B[cr]
;W[hs]
(;B[aq]
;W[es]
;B[as]
;W[dr]C[43 is a fatal mistake, as we can see it costs 6 stones.])
(;B[es]
;W[ar]C[The tesuji of 48 is why Black cannot save the stones.

A disconnect and die situation.]))
(;B[cr]
;W[hs]
;B[es]
;W[ar]
;B[aq]C[If black played 43 correctly, the above would not
have worked])
)
