Stefan Pohl Computer Chess

Home of famous UHO openings and EAS Ratinglist

Patricia - the EAS ChessEngine

The most aggressive superhuman engine ever created

"Patricia is brilliant" - Ed Schroeder (Computerchess legend, author of Rebel engine and famous chesscomputers (Mephisto MM IV, Polgar, Milano, Risc and many more!))

Patricia by Adam Kulju is the first engine besides Ed Schroeder's Rebel EAS, using my EAS-Tool (= Engine Aggressiveness Statistics Tool) to make the engine playing more aggressive:

It's worth noting that Patricia is still well into superhuman territory, with an estimated CCRL elo of 3300-3350; she can put up a solid fight against top engines, and can crush any human or weak engine that dares to oppose her.

Patricia, with an EAS score of 425,000 in gauntlet testing, is leaps and bounds above any engine that has ever existed in terms of attacking, sacrificing, and playing stylishly.

If you think Patricia is a cool project, please spread the word of it! There are lots of people interested in an aggressive engine, whether it be for sparring or for other purposes, and greater awareness of what should be the undisputed queen of style would make their wish come true.

Since the 1950s, the only goal of computerchess was gaining Elo. But in these days of superstrong engines beyond 3700+ Elo, IMHO it makes a lot of sense, to make engines playing more spectacular, aggressive and interesting, instead of just gaining more and more Elo... Since my EAS-Tool was made, it is possible for the first time, to measure the aggressiveness of engines. And so, using the EAS-Tool, to make an engine playing more aggressive, is the next logical step of development in computerchess.

2024/08/07 Patricia 3.1 released. Download here

Android builds (not by A.Kulju, so use at own risk) here

My small Gambit Opening-book (using J.Noomens Gambit-files) for Patricia is here

Folder with DroidFish and Patricia 3.1 armv8 here

ArenaGUI (Windows) with Patricia 3.1 installed and ready for playing here

The author of Patricia (Adam Kulju) wrote this:

"Patricia is, per the EAS tool, unquestionably the most aggressive superhuman chess engine ever created (and the most aggressive engine of any kind that I currently know of).

The metric that Patricia's aggression claims are based off of is Stefan Pohl's EAS-Tool, which is the most well known and well regarded tool for determining the aggressiveness of chess engines. It looks at a combination of factors, such as sacrifice rate, short win rate, and unnecessary draw rate, and outputs a score that captures how "exciting" an engine tends to play.
A huge shoutout to Stefan Pohl. His EAS Tool works wonderfully, makes properly and objectively testing for increase aggression possible, and is the measure by which Patricia development progressed. He was also very invested in Patricia's development and explained many features of the EAS tool to me so that I had a better understanding of what was a sacrifice and what wasn't. He has put a lot of time into quantifying style, and I am happy to have Patricia be a proof-of concept and culmination of his ideas."

I did a testrun of Patricia 3.1 vs. 14 weaker engines of my full UHO ratinglist. Mention, weaker engines means here 3500+ Celo, so these engine are way too strong for Patricia 3.1. You can see the result in the Full UHO Ratinglist

Here the bottom of the Full UHO Ratinglist:

Program Celo + - Games Score Av.Op. Draws

70 Velvet 7.0.0 avx2 : 3504 4 4 16000 30.7% 3653 43.1% 71 Stockfish final HCE : 3499 4 4 16000 40.3% 3570 37.6% 72 Slow Chess 2.9 avx2 : 3475 4 4 16000 38.4% 3563 42.3% 73 Revenge 1.0 avx2 : 3385 5 5 15000 18.3% 3657 30.3% 74 Patricia 3.1 avx2 : 3239 6 6 14000 14.7% 3549 21.1% 75 Patricia 3.0 avx2 : 3235 6 6 14000 14.5% 3549 21.2%

And now, see the top of the EAS full Ratinglist (calculated out of the games played for the Full UHO Ratinglist):

bad avg.win Rank EAS-Score sacs shorts draws moves Engine/player ------------------------------------------------------------------- 1 429481 51.61% 38.03% 05.49% 66 Patricia 3.1 avx2 2 384942 52.55% 35.77% 05.19% 69 Patricia 3.0 avx2 3 197919 31.18% 29.46% 17.09% 71 Revenge 1.0 avx2 4 193706 22.65% 25.49% 08.39% 70 Stockfish 16.1 240224 5 192881 21.25% 26.18% 09.40% 70 Stockfish 16 230630 6 186267 25.24% 24.69% 13.42% 72 Velvet 7.0.0 avx2 7 181381 20.24% 25.04% 10.47% 70 Stockfish 15.1 221204 8 161767 25.14% 21.45% 13.73% 72 Velvet 7.3.0 avx2 9 158026 16.26% 26.23% 11.07% 69 Torch 2 popavx2 10 151721 15.63% 27.12% 13.45% 69 Torch 1 popavx2

This result is really impressive, especially when mentioning, that Patricia 3.1 has won only 589 out of 14000 played games, because the opponents were way too strong !!! (Another impressive proof, that my EAS-Tool recognizes the playing-style of an engine correctly, even though, the opponents were too strong)

Here 20 impressive wins of Patricia 3.1 in this testrun in the pgn-viewer (engines started thinking at move 7).

If you can not see the chessboard, check, that your browser has Javascript activated or if an AdBlocker is the problem.