Chess10 (BBC Micro) by Alci

Chess10

by Alci

Platform: BBC Micro Model B or later models

Language: BBC Basic

Category: Extrem-256 or Schau, both are valid cases.

Instructions:

To play you have to enter your move using board coordinates. You can do it in 2 ways :

?E2 then

?E4

or

?E2,E4

Checkmate is signaled by "#" and stalemate by "=" as in standard chess notation.

Beware there is no validation of the legality of the move. The player must know the rules of chess.

And that's it !

You can also test it in your browser with the url provided in a separate file.

Detailed description:

This a full chess game with a proper engine in 10 lines of BASIC !

BBC BASIC is one of the few BASIC of the 8-bits era allowing recursion. It's also fast, thanks to the "powerful" hardware (2mhz 6502) and clever implementation by Sophie/Roger Wilson. It allows a lot of abbreviation but lines are limited to 239 characters. So I guess it's fair.

It's still in use today and this program can run on BBC BASIC for Windows for maximum performances on modern hardware.

This program is slow by today standards (between 5s and 5 minutes in the worst case by play) but it would have been more acceptable in the eighties. And it would have provided a great educative value !

Features:

- Semi-graphical display

- Clocks for player and computer

- Moves history

- Castling and en passant support for the player

- A proper chess engine

What it lacks:

- A full validation of the player move

- Draw detection by repetition or insufficient material

- underpromotion (Always promote to queen)

- Castling and en passant by the computer

The engine:

- Negamax framework with 2 plies depth

- Quiescent search up to 7 plies depth

- Move ordering

- Square values table (the same for all pieces)

- Mobility score

- Accurate piece and promotion values

See the commented listing for more details.