Optimal play in 'Guess Who?'
Combinatorics
2026-02-17 v4
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.
Keywords
Cite
@article{arxiv.2508.00799,
title = {Optimal play in 'Guess Who?'},
author = {David Cushing and Stuart Gipp and Ezra Levick and Em Rickinson and David I. Stewart},
journal= {arXiv preprint arXiv:2508.00799},
year = {2026}
}
Comments
10 pages; v4 with appendix-of-record containing proof of tripartite case and other edits following referee comments