The first version of my chess engine uses a fixed depth (upto 3 ply) Negamax search that uses alpha-beta pruning. Move ordering is done by randomly shuffling the legal moves at the root of the search. It's eval function is based on sum of piece material values and piece-square tables. It had a weird bug that gave an illegal move.

Move 15 :(

[Event "?"]
[Site "?"]
[Date "2025.08.24"]
[Round "?"]
[White "Leorik"]
[Black "MyPythonChess"]
[Result "1-0"]
[ECO "B02"]
[GameDuration "00:02:08"]
[Opening "Alekhine's defense"]
[PlyCount "29"]
[Termination "illegal move"]
[TimeControl "40/300"]
[Variation "Mokele Mbembe (Buecker) variation"]

1. e4 {+0.17/19 4.6s} Nf6 2. e5 {+0.35/21 4.7s} Ne4 {0.52s}
3. d4 {+0.94/18 5.8s} Nc6 {1.6s} 4. f3 {+2.80/20 4.7s} Nxd4 {1.2s}
5. Qxd4 {+5.43/22 5.6s} Nd6 {1.6s} 6. exd6 {+6.49/21 4.7s} exd6
7. Bd3 {+7.19/20 4.3s} Qe7+ {0.94s} 8. Kf2 {+7.57/19 4.3s} Qe6 {2.0s}
9. Nh3 {+9.01/20 5.5s} c5 {4.6s} 10. Qa4 {+9.90/21 10s} c4 {4.8s}
11. Qxc4 {+10.11/22 5.4s} d5 {2.0s} 12. Qc3 {+10.36/22 7.0s} d4 {4.1s}
13. Qxd4 {+11.79/22 6.0s} Bd6 {5.9s} 14. Re1 {+15.99/22 5.2s} Be5 {15s}
15. Rxe5 {+20.48/21 4.6s, Black makes an illegal move: e6f6} 1-0