Strongly Solving the Royal Game of Ur

We strongly solve three conjectured rule sets for the Royal Game of Ur: Finkel, Blitz, and Masters. For every reachable state, we compute the game-theoretic value, the first player’s probability of winning under optimal play, and an optimal move. From the initial position, these values are 51.54% for Finkel, 50.41% for Blitz, and 50.48% for Masters, implying a small first-player advantage in each variant. We obtain the solution maps using value iteration and the Bellman equations, verify them through convergence analysis and large-scale simulations, and describe practical optimizations that make the computation tractable. The same framework applies to other finite, enumerable variants, and the resulting maps are deployed on RoyalUr.net for optimal play, game review, and player feedback.

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Publication Details

Journal
ICGA Journal
Published
2026-10-30
DOI
https://doi.org/10.1177/13896911261501817
Primary Topic
Artificial Intelligence in Games
Type
article
Field-Weighted Citation Impact
0.00
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article

Strongly Solving the Royal Game of Ur

Padraig X. Lamont, Jeroen Olieslagers
1 links
ICGA Journal
Artificial Intelligence in Games
article

Strongly Solving the Royal Game of Ur

Padraig X. Lamont, Jeroen Olieslagers
article en

Abstract

We strongly solve three conjectured rule sets for the Royal Game of Ur: Finkel, Blitz, and Masters. For every reachable state, we compute the game-theoretic value, the first player’s probability of winning under optimal play, and an optimal move. From the initial position, these values are 51.54% for Finkel, 50.41% for Blitz, and 50.48% for Masters, implying a small first-player advantage in each variant. We obtain the solution maps using value iteration and the Bellman equations, verify them through convergence analysis and large-scale simulations, and describe practical optimizations that make the computation tractable. The same framework applies to other finite, enumerable variants, and the resulting maps are deployed on RoyalUr.net for optimal play, game review, and player feedback.

ICGA Journal
New York University (US)
Openalex Percentile: Top 14%
Artificial Intelligence in Games
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