Video Chess

Name:	Video Chess
Company:	Atari
Model #:	N/A
Programmers:	Bob Whitehead and Larry Wagner
Year:	1978
Released?	No
Notes:	Originally called Computer Chess

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 time.

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.

Although Computer Chess seems to be a complete game, it's still missing some standard features that every chess game needs to have.  The major missing feature is that there are absolutely no promotions!  If you manage to get your pawn across the screen he's stuck there with nothing to do.  Another missing feature is the Check and Checkmate.  While the computer AI is mostly all there, it doesn't understand Check or Checkmate so if you (or the computer) have the king in Check there is no warning nor will the game automatically end if there are no more legal moves (Checkmate).  The computer will also sometimes stop playing once it has taken most of the high ranking pieces.  This is most likely due to a bug in the decision tree the AI uses to select its next move.

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 computer’s pawn.  One way to see this bug is to follow the following steps (special thanks to Nukey Shay for discovering this):

 

1. Most of the time, the AI (playing white) will begin by moving it's kings pawn forward 2 spaces.
2. Threaten this position by moving your queens pawn two
3. The AI will defend its pawn position by moving its queens knight
4. If you then move your kings bishop pawn to threaten the pawn from the opposite side, it responds by taking this one
5. 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.  Computer Chess is an interesting glimpse into the WIP changes that were made in the early days of 2600 programming.

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