Recube vig

As we’ve touched upon before, ownership of the cube has some intrinsic value. This value is oftentimes called the recube vigorish. Vigorish, or vig, is an old-timey word that refers to the small rake taken by a gambling establishment. The general sense is that you’re getting slightly less than you’ve earned because of the vig. In this case, the vig is referring to the fact that the existence of being recubed makes giving the cube away slightly less good for you.

The vig can be calculated exactly and is the reason so many numbers don’t line up when discussing the doubling cube. For example, it’s why the take-point is actually slightly less than 25% (or, correspondingly, slightly less than -0.5 equity). Or why the cubeful equity of a D/T decision is slightly less than twice that of ND. When you give up access to the cube, and give up on being able to “cash” a game, you lose a tiny bit of value.

Most relevant to us, however, is that you need to be aware slightly less willing to give away the cube before redoubling (as opposed to just doubling from the center). In a sense, the “Redouble/Take” window is slightly smaller than the “Double/Take” window, with the “Redouble” boundary being slightly to the right of Point ② in the Doubling Spectrum figure. This is so you can preserve your access to the cube for a little bit longer before giving it up. This change is very subtle but worth noting — sometimes a cube action will be classified as an error, and it will be because you redoubled when you shouldn’t have, even though it’s a perfectly fine double when the cube is centered.

Next lesson: Doubling in racing positions