(;GM[1]FF[4]SZ[19]
GN[Problem 507: Error]
PC[http://senseis.xmp.net/?WeiqiRapidDrill800Problems/Errata]AP[GoWiki:2009]
DT[2009-04-22]
C[Diagram from http://senseis.xmp.net/?WeiqiRapidDrill800Problems/Errata

Problem 507: Error]
PL[B]

AB[pq][rq][or][rr][ps]
AW[op][pp][qp][rp][sp][nq][nr][ns][os]

;B[sq]C[B1]MN[1]
;W[qq]C[W2]MN[2]
;B[qr]C[B3]MN[3]
;W[rs]C[W4]MN[4]
;B[ss]C[B5]MN[5]

;
)
