(;GM[1]FF[4]SZ[19]
GN[Difference game, Black first]
PC[http://senseis.xmp.net/?KyuExercise75/Solution]AP[GoWiki:2009]
DT[2009-04-22]
C[Diagram from http://senseis.xmp.net/?KyuExercise75/Solution

Difference game, Black first]
PL[B]

AB[qm][mn][nn][pn][do][eo][lo][qo][ro][ep][fp][gp][lp][pp][qp][rp][bq][eq][gq][lq][pq][qq][cr][er][fr][lr][mr][pr][qr][ds]
AW[cm][dn][fn][gn][bo][co][ho][oo][po][bp][cp][dp][hp][mp][np][op][cq][dq][hq][mq][oq][rq][dr][gr][hr][nr][or][rr][ps][qs]

;B[br]C[B1]MN[1]
;W[sq]C[W2]MN[2]
;B[ap]C[B3]MN[3]
;W[ao]C[W4]MN[4]
;B[aq]C[B5]MN[5]
;W[sp]C[W6]MN[6]
;B[so]C[B7]MN[7]

;
)
