This tool shows how cube action in the 5-point holding game changes as the race changes. White holds an anchor on Blue's 5-point, the position often called the 20-point holding game, and Blue is on roll with the cube centered in an unlimited game. An unlimited game means a game that stands alone, where match score does not affect the decision.

Pick a structure, then slide to change Blue's race lead. The color strip shows where Blue's double arrives and where White's take ends. The twelve structures sit in three rows: how many checkers Blue has on the midpoint, what else changes for Blue, and what changes on White's side.

Each step asks two questions: should Blue double, and if Blue doubles, should White take or pass? Every step has been fully evaluated. The best action earns a green BEST badge. An action that gives up a little equity is an ERROR; one that gives up a lot is a BLUNDER. Have fun.