Optimal play in 'Guess Who?'

TL;DR

This paper derives an optimal strategy for the game Guess Who? under official rules, introducing a novel technique that allows for tripartite responses, enhancing strategic decision-making.

Contribution

It presents the first known optimal strategy for Guess Who? and introduces a new method for handling tripartite responses in game questions.

Findings

Optimal strategy for Guess Who? established

Technique for tripartite responses explained and applied

Enhanced strategic questions improve gameplay analysis

Abstract

We prove an optimal strategy for the children's game Guess Who? assuming the official rules are in use and that both players ask `classical' questions with a bipartite response. Applying a technique described in [Rabern, B \& Rabern, L 2008, 'A simple solution to the hardest logic puzzle ever', \textit{Analysis}, vol. 68, no. 2, pp.~105-112.] allows for questions with tripartite responses; we explain this innovation and give an optimal strategy for two players applying it.