(;GM[1]FF[4]SZ[19]
GN[Main line.]
PC[http://senseis.xmp.net/?RTGProblem4/Solution]AP[GoWiki:2009]
DT[2009-04-22]
C[Diagram from http://senseis.xmp.net/?RTGProblem4/Solution

Main line.]
PL[W]

AB[pq][qq][nr][pr][rr]
AW[mp][op][pp][qp][rp][lq][rq][kr][mr]

;W[qs]C[W1]MN[1]
;B[sr]C[B2]MN[2]
;W[ns]C[W3]MN[3]
;B[os]C[B4]MN[4]
;W[oq]C[W5]MN[5]
;B[rs]C[B6]MN[6]
;W[or]C[W7]MN[7]
;B[ms]C[B8]MN[8]
;W[ps]C[W9]MN[9]

;
)
