|Bob Whitehead and Larry Wagner
Back in the early days of computing, having a Chess game
for your computer was considered a must. Not only did it
show that computers could be used for 'intelligent recreation',
but it also helped show off the raw power of your system.
This obsession also trickled down to game consoles even though
most of them were woefully underpowered for something as
demanding as Chess. Still, game companies managed to get a
Chess game on almost every system (sometimes cheating with extra
hardware), and the Atari 2600 was no exception. The funny
thing is though, Atari wasn't originally planning on bringing
Chess to the 2600 at all!
You see, Atari was in a bit of pickle at the
time. They were currently being sued for lack of a Chess
cartridge. Atari had never planned to do a chess program as
everyone thought that Chess was well beyond the capabilities of
the 2600. However someone forgot to tell marketing this and
they stuck a big ol' Chess piece on the system box (original 1977
version only). 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
a lot of money in lawsuits. Thus Video Chess was born.
So now that you know the history behind Video
Chess, how does it play? Well, while the computer AI
won't win any awards for speed, it does play a competent game
of Chess. Video Chess has eight different variations
(skill levels) ranging from beginner to expert. The
easiest skill levels will allow even the most novice Chess
player a chance to beat computer, while the harder levels will
give expert players a run for their money. The only
problem is that due to the low amount of RAM available and the
slow processor of the 2600, the computer can take 10-20
minutes per move at the intermediate levels and several HOURS
at the highest levels. In order to free up as much RAM
and processor time for the computer to think, the screen is
blanked out when the computer is computing its move. To
let people know that the 2600 was merely thinking and not
dead, they made the screen flash different colors during this
Video 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. Some of the things that were axed to
free up space were the Chess notation that was originally
displayed in the Computer Chess prototype and two of the highest
skill levels. This was probably a good trade off to save
costs. While the notation might have been missed by the more
serious Chess players the average Joe probably didn't even notice,
and the two missing variations were borderline unplayable given
how long they took between moves.
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.
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 C.
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