Baby Poker is a two-player dice game that fits on a napkin and still manages to be a real bluffing game. Each player rolls a single die concealed in a cup. There is one round of betting. That is it. And yet the optimal strategy involves mixed frequencies, a value range, a bluffing range, and a call/fold cutoff. It is the smallest game I know of that has all the moving parts of full poker.
Our working notes: Baby Poker.
The Problem
This one comes from the FiveThirtyEight Riddler column (now defunct, but happily still on the Wayback Machine …