(;GM[1]FF[4]SZ[21:9]
GN[On the left, White can't place a pawn on the marked point because the number of surrounded groups is increased. They can't place a king there, either, because the number of surrounded enemy groups is not increased. Black, however, can place a king on that point and remove all pawns from the newly surrounded white group, as shown on the right.]
PC[http://senseis.xmp.net/?Yugo]AP[GoWiki:2009]
DT[2017-06-04]
C[Diagram from http://senseis.xmp.net/?Yugo

On the left, White can't place a pawn on the marked point because the number of surrounded groups is increased. They can't place a king there, either, because the number of surrounded enemy groups is not increased. Black, however, can place a king on that point and remove all pawns from the newly surrounded white group, as shown on the right.]
PL[B]

AB[ac][bc][cc][mc][nc][oc][dd][ed][pd][qd][fe][ne][re][af][ef][ff][mf][qf][rf][bg][cg][dg][ng][og][pg]
AW[ad][bd][cd][od][ae][ce][de][ee][oe][bf][cf][df][pf]
CR[be]
SQ[cd][od][ce][ne][oe][df][pf][cg][og]


;CR[be]
SQ[cd][od][ce][ne][oe][df][pf][cg][og]
)
