(;GM[1]FF[4]SZ[20:19]
GN[Easiest to understand]
PC[http://senseis.xmp.net/?PreventingEscapeOnTheFirstLine]AP[GoWiki:2009]
DT[2009-04-22]
C[Diagram from http://senseis.xmp.net/?PreventingEscapeOnTheFirstLine

Easiest to understand]
PL[W]

AB[ea][fa][ga][ha][ia][ja][ka][la][ma][na][oa][ab][bb][cb][db]
AW[ba][eb][fb][gb][hb][ib][jb][kb][lb][mb][nb][ob][bc][cc][dc][ec][be]

;W[pb]C[W21]MN[21]
;B[pa]C[B22]MN[22]
;W[qb]C[W23]MN[23]
;B[qa]C[B24]MN[24]
;W[rb]C[W25]MN[25]
;B[ra]C[B26]MN[26]
;W[sb]C[W27]MN[27]
;B[sa]C[B28]MN[28]
;W[tb]C[W29]MN[29]

;
)
