Why a reachable position can have at most 218 playable moves
Why a reachable position can have at most 218 playable moves
This article by Tobs40 on Lichess.org investigates the maximum number of legal moves possible from a single chess position. It aims to mathematically prove that 218 is the absolute upper bound, building upon the 1964 record composition by grandmaster Nenad Petrović. The author details their computational approach using integer programming with Gurobi, including various optimization strategies and challenges encountered. The work successfully confirms 218 as the limit for reachable positions and also confirms 144 moves for positions without promotions, referencing Jenő Bán's 1960 discovery.
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that faq at the end is a must read. that title sent me for a spin.
fun to see the little logical hacts that have big impacts on runtime.
yet more amazing someone out out the solution more than 50 years ago!
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