DroidFish Chess

July 2025

SupeUltra Network

# Superultra (NNUE) ## Overview Superultra is a UCI compliant chess engine that uses an alpha-beta search framework, various heuristics and optimization techniques, and an efficiently updatable neural network (NNUE) in order to analyze chess positions and calculate moves. ## Usage Superultra supports the UCI Protocol but does not come with a GUI (like most UCI chess engines). It is recomended to download a UCI Compatable GUI such as cutechess. ## Features ### Board Representation * Bitboards * Magic Bitboards for efficient slider attack generation ### Search * Iterative Deepening * Aspiration Windows * Parallel Search with Lazy SMP * Principle Variation Search * Transposition Table with 4 buckets and aging (shared across threads) * Move Ordering * Countermove Heuristic * Killer Heuristic * Continuation History Heuristic and History Heuristic (with gravity) * MVV/LVA * SEE * Transposition Table Move * Pruning, Reductions, and Extensions * Null Move Pruning * Razoring * Reverse Futility Pruning * Probcut * Quiet Move Pruning * Move Count Pruning * Futility Pruning * History Pruning * SEE Pruning * Singular Extensions + Multicut Pruning * Late Move Reductions * Quiescence Search * Time Management * Best move stability * Score stability * Complexity based on the percentage of time spent searching moves that are not the best move ### Evaluation * Efficiently Updatable Neural Network * (768x10-->512)x2-->1 architecture * Perspective * Crelu Activation Function * 10 King Buckets (mirrored) * 8 Output Weight Buckets

Top-15 June 2025

Stockfish dev-20250525-73c55e89 https://github.com/official-stockfish/Stockfish/releases/tag/stockfish-dev-20250525-73c55e89

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Stockfish dev-20250427-94e6c049 https://github.com/official-stockfish/Stockfish/releases/tag/stockfish-dev-20250427-94e6c049