(;GM[1]FF[4]SZ[19]
GN[Black cannot escape]
PC[http://senseis.xmp.net/?PreventingEscapeOnTheFirstLine]AP[GoWiki:2009]
DT[2009-04-22]
C[Diagram from http://senseis.xmp.net/?PreventingEscapeOnTheFirstLine

Black cannot escape]
PL[B]

AB[da][ab][bb][cb][db]
AW[ba][eb][fb][bc][cc][dc][ec][be]

;B[ea]C[B1]MN[1]
;W[fa]C[W2]MN[2]
;B[ac]C[B3]MN[3]
;W[ad]C[W4]MN[4]

;
)
