|Bob Whitehead and Larry Wagner
|The only known
prototype that has a production end label.
Chess is a bit of an oddity among prototypes. Once
thought to simply be an early name for Video Chess, it turns
out that Computer Chess is actually a slightly different and
earlier version of the game. While there arenít a ton
of differences (Chess is Chess), there are still enough to
The first (and most obvious) difference is that the coordinates
for the chess board is displayed at the bottom of screen.
When a piece is selected, a picture of the piece and the
coordinates of the move (in Chess notation of course) are
displayed on screen. This was probably removed from the
final version (Video Chess) because most players aren't familiar
with Chess notation and would be confused by all the numbers and
letters all over the screen.
Another major difference in Computer Chess is that there are
no pawn promotions, the feature simply isnít in the game
yet. If a pawn reaches the other side of the board
it will simply be stuck there, unable to move. Since
Computer Chess also lacks the Ďsetup modeí found in Video
Chess the player canít manually promote their pawns
either. The lack of pawn promotions really breaks some
major strategies, making the game a bit tougher (although the
computer canít do it either so it evens out a bit).
Some other minor differences in Computer Chess are
that it's played using the right joystick. I can't offer any
explanation for this except that it might be a programming
bug. Computer Chess also displays the difficulty level in
the bottom left corner as C# (# being the difficulty level), Video
Chess simply displays a large number at the top of the
screen. Computer Chess also makes some psychedelic sounds to
go along with the flashing colors is shows when its
thinking. These were wisely taken out of Video Chess.
Interestingly, Computer Chess has a minor (but amusing) bug
in it that was fixed in the final version. If the player
and computer follow a certain series of moves it is possible for
the player to take control of the computerís pawn. One way
to see this bug is to follow the following steps (special thanks
to Nukey Shay for discovering this):
- Most of the time, the AI (playing white) will begin by
moving it's kings pawn forward 2 spaces.
- Threaten this position by moving your queens pawn two
- The AI will defend its pawn position by moving its queens
- If you then move your kings bishop pawn to threaten the pawn
from the opposite side, it responds by taking this one
- The victorious pawn is now yours!
Did you ever notice how the chess pieces are made
up of lines? This is because of a special trick created by
Bob Whitehead to display more than six sprites per line (which
wouldn't have been enough for Chess). This trick called
"Venetian Blinds" allowed the 2600 to display up to eight sprites
per row (instead of the normal six) by alternating them between
two sets of scanlines (four on one set of scanlines, and four on
the other). It was the development of this trick that made a
chess program on the 2600 possible.
It's a good thing that Atari was able to figure
this out, as they were currently being sued for lack of a Chess
cartridge! You see Atari had never planned to do a chess
program. Everyone thought that Chess was well beyond the
capabilities of the poor old 2600 so it was never planned.
However someone forgot to tell marketing this, and they
stuck a big ol' Chess piece on the system box. Apparently
some man in Florida had bought the 2600 assuming that it would
have a Chess program available (after all they advertised it right
on the box!). After realizing that Atari planned no such
thing, he sued for false advertising. So Atari could either
cough up a Chess cartridge or pay out alot of money in lawsuits,
and thus Computer Chess (later renamed Video Chess) was born.
So after much research it has been concluded that
Computer Chess is really an early version of the program that
eventually become Video Chess. Interestingly Computer Chess
was the first 2600 game to break the 4K barrier, originally
weighing in at a hefty 6K! Rather than go through the
expense of releasing Computer Chess as a bankwitched cart, Atari
decided to strip it down so it could fit into a regular 4K
cart. Unfortunately it appears that the chess notation was
one of the features that had to be axed to make room for pawn
promotions, setup mode, and other bug fixes. Computer Chess
is an interesting glimpse into the WIP changes that were made in
the early days of 2600 programming.
||EPROM board only
||Prototype cart has a production
to 2600 Software