Legacy computer programs and engines

Hello, I recently registered here to rekindle my interest for chess. In the last 15 years I must have played less than 20 chess games, so I am just a novice. I am a programmer and also interested in emulation, I was reading an article about the evolution of the chess engines (german):

http://www.andreadrian.de/schach/index.html

I managed to get the program 8080 Chess (from 1977) working on an emulator called Solace for the Sol-20 personal computer and played two games against it. Its playing is pretty serviceable, considering the whole program is 5881 bytes.

Here is a screenshot:

I assume I can get the emulator, chess program, and manual from the sol20.org site? Do you have any other tips I need to be aware of?

For example, do I just put the ENT file in some folder, and if so, which folder?

(I skimmed the manual - Chesspersons? Really? )

Hm, yes, it's very easy, get the emulator here:

http://www.sol20.org/solace.html

And in the programs page, here, you can get the 8080 Chess:

http://www.sol20.org/programs.html

Extract the ent files that interest you in the Solace/binaries folder and load them from the emulator. Then, if they are loaded into address 0, use the "EX 0" command. Capital letters are important. Look here for notes for the correct operation of the program:

http://www.sol20.org/schaper/chessa4.html

I was tempted to change its default search depth but in that site I read that it may get stuck in complex situations because of not enough stack memory, so I left it at default (3). As I was playing I did notice that the depth showed 4 a couple of times, though.

You can see from my two games that it plays weakly but "reasonably", in my amateur opinion. I think that is a big deal for a computer program from 1977. I will later make another post with weird niche engines I found

EDIT: Ah, yes, the manual is a goldmine in some respects

EDIT: I checked the manual for the depth. Maybe it gets to above 3 when it is capturing, those are special cases it seems.

I can't believe it's only 5800 bytes!

@OP, thanks for the tips. I'm fairly busy today, but I hope to play with it in the next few days.

Oh, yeah, look at this crazy coder:

http://nanochess.org/chess6.html

His minimalist chess program/engine is 392 bytes!

I decided to play the Atomchess Reloaded version which is 754 bytes because the smaller one doesn't have castling, en passant etc, so I don't consider it complete enough.

Here is a game I played against this tiny thing (it is compiled into a DOS com executable, runnning under Dosbox)

The source for the two versions is here (in assembly of course):

https://github.com/nanochess/Toledo-Atomchess

I have also had some fun with old programs, and have even written a number on blog posts on my profile about some of them. I have testet 8080 Chess also, and may do a write-up on it in the future. Actually I came over your post while googling more info about the program.

One of the interesting things about 8080 is that it is the first microcomputer program to participate in the ACM North American Computer Chess Championship in 1977. It ended 9/12 after one win (against Ostrich running on a Nova 3 minicomputer) and three losses.

8080 Chess does indeed spend more time thinking when there are captures involved. According to the manual, at the default level the computer thinks 3 plies deep, and if there are capture it may think up to 2 additional plies. So far I have only tested the program at the default difficulty. One thing I would like to find out, though, is if the participation in the ACM championship was done using the default difficulty level or if it was tuned somehow to suit the time control used. But I have not been able to find any information about this as of yet.

BTW, Microchess by Peter Jennings (a program I have written a blog post about) is also available for the SOL-20 on the sol20.org website, and can be run in Solace. Though personally I prefer the Apple II version of Microchess 2.0 :-)

Answering my own question:

I have managed to dig up a total of 5 old games played by 8080 Chess. 4 of these are from the already mentioned ACM in 1977. The last game is one of the games from the 1978 Micro Computer Chess Tournament in San Jose.

8080 did indeed win one game in ACM against a minicomputer running Ostrich, but the manner in which it won was less than impressive. I came over the explanation for this game digging through old magazines on archive.org, and it turns out that Ostrich actually had a completely winning position in this game. But alas, when Ostrich was about to deliver the final mating blow it crashed, and was subsequently forfeited.

About the playing level used: I have tried to reproduce the 8080 moves using the Solace emulator, and it deviates under default 3+2 settings. When I crank it up to 5+2 it starts to play the moves from the old games, so I assume that the program was tuned to the stipulated tournament time controls. But maybe they tuned them a bit too much, because in the very next game 8080 lost on time after 16 moves! I have not found an explanation for this, but I can only speculate that the authors underestimated the effect of the higher ply search on complex positions, and the program ran out of time.

One benefit of emulating in Solace, though, is that you can speed up the emulation by a factor of at least 100x, making it suitable to test 8080 at higher levels if you wish.

Finally, one game against the Commodore Chessmate from MCCT 1978. AFAIK the Chessmate is running a version of the already mentioned Microchess.

Where do you find all this information and games about old computer chess tourneys?

Also, those two games are like games between kids. I don't think I would figure out they were played by computers if I randomly saw  them

There are plenty of good sources for old games. For a head start, check out http://www.top-5000.nl/pgn.htm which collects PGNs for a number of tournaments.

ICGA also has a lot of old tournaments where you can get PGNs. http://www.game-ai-forum.org/icga-tournaments/

Chess Computer UK has collected a lot of old information in PDF format. http://www.chesscomputeruk.com/html/publications.html

And if you are prepared to _really_ get your hands dirty you can head over to https://archive.org/ and start digging through some old magazines from the 70s. Personal Computing in particular had a running chess column from 1970s and onwards, specifically reporting from computer chess tournaments.

And yeah, computers in the 70s were pretty weak, especially home computers, which both of the two computers in the last game was.

I played a couple of games against Video Chess on the Atari 2600. It is from 1979. I set it to difficulty level 5, it thinks from 20 seconds up to about 3 minutes.

I was feeling confident in the second game as Black but I missed a spiffy tactic and had to settle for a draw. Even a weak computer from before I was born gives me a serious challenge, damnnn

Nice, I have tested Atari Video Chess too. If level 5 is too tought, feel free to drop down to lower levels.

I am currently looking into the Sargon series of programs. Sargon 1 is easy. Sargon II puts up a little bit of a fight, but I can still take it down. Now I am testing Sargon III for the 16 bit computers (Atari, Amiga etc) and I can beat it at blitz games. Haven't tested it on longer time controls yet.

I can beat Video Chess at level 5 overall. Yesterday I played two games against Chessmaster for the Gameboy Color (on the Retroarch emulator) The difficulty was set at 60/5 with Deep Thinking disabled (it is the Ponder option of modern engines) It literally handed me he win with a direct blunder.

This is how it looks:

In the second game it saced a minorpiece to expose my king but played some weak moves and then dropped all the pawns for some reason lol