(;GM[1]FF[4]SZ[19]
GN[B1 normally increases one liberty]
PC[https://senseis.xmp.net/?GokyoShumyoSection4Problem30/Solution]AP[GoWiki:2009]
DT[2022-12-29]
C[Diagram from https://senseis.xmp.net/?GokyoShumyoSection4Problem30/Solution

B1 normally increases one liberty]
PL[B]

AB[gb][ec][fc][cd][dd][fd][be][ge][df][gf][cg]
AW[hb][bc][cc][dc][gc][ic][bd][ed][gd][ee][fe]
LB[ea:c][fa:e][cb:a][eb:d][ef:b]

;B[db]C[B1]MN[1]

;LB[ea:c][fa:e][cb:a][eb:d][ef:b]
)
