Yugo

Yugo is a finite Go variant where permanent pieces of the player's color are used for moves that increase the number of surrounded enemy groups. After such a move, all non-permanent pieces in those enemy groups are removed, and then all non-permanent pieces in friendly groups that remain surrounded are also removed. If the surrounded enemy groups only contain permanent pieces, no pieces are removed from them, but the move is still legal.

Regular pieces are used for moves that don't increase the number of surrounded groups of any color. Placements that surround one or more friendly groups but no enemy groups are illegal.

Area scoring, integer komi and the button are used; surrounded groups of permanent pieces score for the opponent. Permanent pieces are called kings; regular pieces are called pawns.

Luis Bolaños Mures designed Yugo in March, 2017.

Examples

Stones with red squares in them represent kings.

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.

On the left, White can place a king on the marked point, which increases the number of surrounded groups of both colors. The surrounded black group is checked for removals first, but none are possible, as it contains no pawns. Next, since the white group remains surrounded, the pawn that it contains is removed, as shown on the right.