Chess

This document describes the Greenblatt Chess Program, also known as MACHACK, a chess program written in FORTRAN and submitted to the DECUS Program Library in June 1970. Contributed by Tymshare, Intergalactic Computer Operations, California, USA, it was designed to run on the DEC PDP-6/10 time-sharing monitor.

The program allows users to:

• Play against MACHACK as either Black (PB) or White (PW).
• Have MACHACK play against itself (PS).
• Display the game (PG) or current board position (BD).
• Configure MACHACK's move examination strategy by setting the "width" (number of plausible moves considered per ply, using SETW and SETW ARG1 ARG2 ARG3...) and "depth" (using SETD and SETD ARG) of its analysis. Suggested settings for "hacker" and "tournament" modes are provided.
• Control the game with commands like M (MACHACK makes a move), U (unmove/take back last move), and RESET (reset game to beginning).

Moves are entered and displayed using a pseudo-standard chess notation, which includes support for full or abbreviated forms, special characters for captures, and specific notations for castling (0-0 for kingside, 0-0-0 for queenside). Piece designations are standard (K, Q, B, N, R, P). The document includes an example of a game interaction.

A disclaimer notes that while the program was tested by the contributor, no warranty is made by DECUS or Digital Equipment Corporation regarding its accuracy or functioning.