wwce

World's Worst Chess Engine

I challenged myself to write a rudimenatary chess engine in four hours. That initial challenge was a qualified success. The resulting executable is under 1000 lines of code including comments, and under 64K compiled (on a Macbook).

Here's what's missing to make it really Chess:

1. Pawn promotion
2. En passant
3. Castling
4. Draw detection
5. Checkmate detection

Here's what's very basic:

1. No player input (plays only with itself)
2. No understanding of openings
3. No understanding of end game
4. No look-ahead
5. Trivial position evaluation (avoid check and min-max the point value of pieces remaining on the board)
6. Selects randomly among moves with equal position evaluations
7. No clock
8. Non-standard move notation
9. ASCII board render (upper case is White, lower case is Black, a "." indicates an empty black square.)

Known bugs:

1. Inverted numbering of board ranks
2. Black square display algorithm doesn't properly alternate ranks
3. Random number generator is not seeded; all runs are the same
4. On its first move a pawn will jump over an intervening piece to move two squares

I gave myself this challenge after answering two chess-related questions on Quora. The first was whether an employer should be impressed that a candidate wrote a chess engine. The second was what's the next-worst chess engine after a "random mover."

The bugfixes branch (https://github.com/cyberabi/wwce/tree/bugfixes) has incremental improvements to wwce to address the issues called out above. The main branch has the original 4 hour project. Don't code like this. MIT License. Have fun!

Chris Burke chris@cyberabi.com 01/25/2023