Duo Cast

The opening throw

Two dice. Seven or eleven on the opening throw settles at once in your favour; two, three or twelve settles against you. Anything else becomes the mark.

Chasing the mark

Once a mark is set, the dice are thrown again and again. Repeating the mark settles in your favour; a seven before it settles against you. Nothing else has any effect.

The side covers

Beside the main cover you can back the mark directly, at odds that match its true chance exactly — the only field on this site with no margin at all.

Why seven is the pivot

Seven can be built six ways out of thirty-six; six and eight five ways each; four and ten only three. Every rule in this game exists because seven is the most common total.

Where 1.41 percent comes from

Add the opening-throw outcomes to the mark-chasing ones, weighted by how often each mark is set, and the whole thing lands 1.41 percent short of even. That is one of the narrowest margins in any dice game.

Everything is countable

Two dice have thirty-six outcomes and three have two hundred and sixteen. You can write them all down on one page, which is why dice are the best place to learn where odds come from.

The shape of a total

Seven appears six times out of thirty-six and twelve appears once. Nothing is weighted; the shape comes purely from how many ways a total can be built. Most confusion about dice starts with forgetting that.

Wide margins hide in exotic covers

The simple covers on a dice table are among the fairest anywhere. The exotic ones — an exact triple, a rare total — carry the widest margins on this whole site, and they are the ones printed largest.

Rituals and results

Blowing on the dice, throwing harder, choosing a moment. None of it moves a single outcome. The rituals are old and human and completely without effect, and that is worth knowing before you start attributing results to them.