Classic Computer Magazine Archive COMPUTE! ISSUE 21 / FEBRUARY 1982 / PAGE 121

A Correction For Progressive Computing Chess 1.9

Dave Leskin
Calgary, Canada

Progressive Computing, based in Windsor Ontario, is an excellent source of OSI software with prompt and courteous service; however, there is a major error in their tape version of "Chess 1.9". This error is found in the opening tables. If you try the following sequence of moves you can determine if your copy of "Chess 1.9" has this error too. Note that the last move by the computer is illegal. Micro-chess notation in brackets.

Computer (White) Human (Black)
1 P-K4 (13-33) P-K4 (63-43)
2 N-KB3 (01-22) N-QB3 (76-55)
3 B-QN5 (02-46) N-KB3 (71-52)
4 B-KN5 (05-41) ???

As you see the "B-KN5" jumps right over the Queen Pawn at 14. To solve this problem I changed the program so that the Queen Knight was moved from 06 to 25 instead. This results in a "Four Knights Game" which is a common opening used by many players. Just follow the steps listed below to effect the change.

The Changes

  1. Load "Chess 1.9"
  2. Press "D" to enter monitor once the board appears.
  3. Press ".0B34"
  4. Press "/" to enter the data mode
  5. Press "25" which refers to the square that the piece will be moved to
  6. Press the "RETURN" key
  7. Press "07" which refers to the piece to be moved—in this case the Queen Knight
  8. Press ".03AC" and "G" to return to the program

Now the program will respond N-QB3 in place of B-KN5 each time this opening sequence occurs. If you have the capability to store machine code programs (Aardvark's "AUTOLOADER" or "C1E" ROM) then record the modified version (otherwise you'll have to follow the above procedure each time you power up).