Live online backgammonBoardgammon
EnglishEN
LanguageChoose your language
11

Backgammon glossary · J

Janowski formula

The standard formula for cubeful equity, blending the dead-cube and live-cube extremes.

How it works in play

Real cubes are neither fully live nor dead. Rick Janowski’s formula estimates cubeful equity by blending the two extremes, weighted by how efficiently the cube can be used in the kind of position at hand; engines such as GNU Backgammon use this kind of blend for their cubeful evaluations.

  • Cube life — The remaining value of cube ownership; quantified by Janowski’s live-cube calculations.
  • Live cube — A cube that can still be re-doubled, as opposed to a "dead cube."
  • Cubeful / cubeless equity — A position’s expected value with and without future cube actions accounted for.
  • Take point — The minimum winning probability at which taking a double breaks even — about 25% in money play; score-dependent in matches.

Go deeper

In other languages