This tool shows how cube action in a blitz changes with the number of Blue checkers in the zone. The zone is Blue's points 1 through 11: a checker there can hit a White checker in Blue's home board or help close a point. White has checkers on the bar and no anchor, 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.

Every tab starts from a real blitz position, and the slider moves Blue's checkers between the midpoint and the zone, so you can see how many Blue needs. The first row changes Blue's home board. The second row changes where White's loose checker sits. The third row changes White's side: a stronger home board or a second checker on the bar. The color strip shows where Blue's double arrives and where White's take ends.

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.