Can a chess engine play like Morphy?

Can top chess engines play brilliant sacs like Morphy and Tal did, or do they just strictly play positional moves till they grind the opponent down for a win?   

If a brilliant sac is on the board, any good engine should see it and play it. 

Some engines can make speculative moves, although they're in the minority. The old (commercial) Chess System Tal program had that reputation.

On the other hand, engines (except maybe what EschereshcsE is talking about) won't make brilliant sacs that don't work against best defense.

If the sac is sound,then why not?

There are two types of sacrifices: The correct ones and mine.

 - Mikhail Tal

The thing about Morphy's play is that the level of positional understanding and defensive resources for one's opponent was quite different in that day than today. 

While chess engines can be tuned to play very aggressively, it is hard to make them "ignore" defensive and positional options the oponent may have at their disposal that the oponent isn't likely to see.

This is really the crux of the difference between humans and chess engines. There are moves that even fairly good chess players don't consider because they don't seem right, or they rely on a deep understanding of some chess-board geometry that players of a certain level won't see.

But computers aren't a very good judge of what sorts of moves are intuitive and which one's aren't.  

So if i'm understanging this right, a top  chess engine will not make a sac play IF there is a sound defense against it that could beat the sac play?    That chess system Tal program sounds interesting.      

(Top) Engines assume the best defense. So if there are a million bad defenses and just a single good defense, the engine will assume his opponent will play that single good defense (assuming the engine actually found this single good defense).

Exactly. But the issue of "playing like Morphy" is more complicated than the notion of if there is a single defense or not. It's that the computer can't determine if that single best move is a move that a player of a particular level will see or not. 

Sometimes "only moves" are increadibly obvious to even low level players. Other times "only moves" are only found after decades of analysis by top GMs. 

One of those two cases is the basis of playing like Morphy, the other is the basis of playing like a pure patzer. 

The downside of Chess System Tal (CST) is that it was a proprietary GUI (engine was not UCI or WB and could only run in the CST GUI). Compared to top engines of the day, it wasn't among the strongest. However, for the average patzer, even the weak levels could be hard to beat. I think the AI Factory still offers a download version under the name Chess Tal Classic.

Here's some interesting links:

http://chessprogramming.wikispaces.com/Chess+System+Tal

http://www.aifactory.co.uk/AIF_Games_Chess_Tal.htm

http://adamsccpages.blogspot.com/2012/07/chess-system-programs-of-chris.html#more

Thanks Esch, i found 2 of those links on my own, and tried to download one, then i think it automatically tried to download Norton on me, trying to get me to buy Norton - seems it was a trick.  Had to uninstall of that crud.  Checking out your 2nd link now.  edit: yep, that one was a sales pitch too. . . cost about $25.  Oh well, forget it, I'll just read Attack Like Tal. 

Yeah, the AI Factory does charge for the program. Apparently they still own the source code. You could try the freeware predecessor "Complete Chess System". It's Dos, and you'd want to install it in DosBox (with the D-Fend Reloaded front-end). Links to Complete Chess System and DosBox/D-Fend Reloaded here at Ed Schroeder's web site:

http://www.top-5000.nl/cp.htm

Thanks for the try, tried to get it, said something in my computer wasn't installed to download it.  i suck today at trying to download stuff. 

chessmaster at one time tried to emulate the styles of famous players.  It can be done, I think.  All you have to do is give it a database of the player's games + engine settings to favor a particular style, which really means a modification to a single function in the engine.  Change the function that selects the best move (or the function that scores moves, whatever) so that it favors moves that fit the style given so long as they are within X points of the "best" move from the normal engine calculations.  Between the move selection and the database (to help choose openings and endgame responses) it should be an approximation of the human.

I hope this post is of interest to some of you guys, otherwise I've just wasted a good amount of time writing this up.  (Digging up all of the download links was a real chore!)

I've been spending some time for the past few days searching the web for aggressive engines, and I think I've found some. The commercial ones typically could play at weakened levels, but they aren't available any more. Most of the free ones can only play at full strength, but four or five do have reduced strength settings. I doubt that these engines can really play like Tal, but they should at least be more interesting than your run-of-the-mill engine. I'm not really strong enough to appreciate all of the deep tactics, so I basically had to rely on other people's recommendations. The strength of these engines ranges from about 2300 to maybe 2900 at full strength; More than enough firepower for playing against, but clearly not the best for analysis.

Here's my list:


Commercial engines/programs:

1) Junior 7 - An old engine, no longer offered. You'd have to scrounge this one up on eBay, etc. (No, I don't have this one.) The consensus is that this is the most aggressive commercial engine ever created. Rating about 2550 CCRL. You can get a free crippled demo of the current Deep Junior version. I don't know f it's as wild as Junior 7 though. Apparently it's limited to 16 plies in depth (8 full moves). I may give this demo a try.

Link to Deep Junior demo:  http://www.hiarcs.com/pc-chess-junior-download.htm

2) Mchess Pro 8 program (DOS) - I'm throwing a couple of bones to the retro DOS guys. A few people mentioned Mchess, even though it's long been off the market. If you did manage to get a copy, you'd have to run it in DosBox with the D-Fend Reloaded front-end, or in a virtual Dos environment.

Michael Reyes - "MChess - Rated as the second most aggressive engine in the retro list I mentioned. From the games it played, I'd say they were right about its style."

3) Chess Tiger - Used to be sold by Lokasoft, but is no longer available. Not quite as wild as Junior 7, but wild enough. About 2700 CCRL.

4) Rebel 12 - Again, used to be sold by Lokasoft, but is no longer available. 2575 CCRL.

Ruxy Sylwyka - "The engine itself plays a magnificent chess. In endgame it's not a strong engine (without TBS access , only internal BBS). Maybe the results weren't so great ( despite the fact that in epoch was a strong chess engine ) but its play ( sacrificial) is ravishing regardless of opponent. I like a lot this engine! ProDeo is more strong but losted a lot of from the style of his little brother."

Robert Flesher - "To me is seems to play in a style like no other, yet close to Deep Junior 7.0. Very aggressive, go for the throat chess...I have bright, very tactical engine, but it seems confused(positionally), almost to chaotic. I prefer Deep Junior 7.0 and now Rebel 12 because they often sac material based on attack possibilities that other engines do not even consider. There is no easy draw! Try to lock the position with Rebel , he will take it personal. Then soon after you will see the sac of one or several minor pieces to smash you happy fortress. This is if you manage to even get one. I prefer to avoid bad chess ideas like that, but it good to know Rebel can deal with them."

5) Chess System Tal II - Already discussed in prior posts.


Free engines/programs:

Note: Most logos for chess engines can be obtained from Chess Mosaic:  http://www.chessmosaic.com/ListOfAllEngines1.html

1) Comet A90 engine (WB protocol) - Maybe 2250? Full strength only.

A quote from an admirer: Ruxy Sylwyka - "Both Comet A90 & ZChess 2.00 are Legatus Augusti of Computer Chess Imperium! Hard to find something similar in our days. Houdinello Futurello the 3-rd is a sort of Cassius Clay not a Velasquez! Sorry, Robby! O tempora!"

Download link:  http://web.archive.org/web/20061012030731fw_/http://wbec-ridderkerk.nl/html/enginleft.htm

****(See Edit note below the Comet.ics config file!)****
The COMET.ICS configuration file supplied with the engine only has a few commands. Here's one with more commands. You should change the values to suite your setup:

MAX_HASH [nr of megabytes]:128
PONDER [ON or OFF]: OFF
SELECTIVITY [ON or OFF]: ON
BOOK [ON or OFF]: ON
RESIGN [ON or OFF]: OFF
OFFER_DRAW [ON or OFF]: OFF
ICS-INFO [ON or OFF]: OFF
TB_PATH: C:\egtb
TB_CACHE [nr of megabytes]:16
SHOW_PONDER [ON or OFF]: OFF
ENGINE_BEEP [ON or OFF]: OFF

Edit - I think I may have been given bad info. I finally set up Comet A90 and got it running, but I can't for the life of me get it to stop resigning in a lost game (greater than a rook down) or get it to use tablebases. It's beginning to look to me like only the first four lines of the config file above are valid for version A90. I'm guessing that the rest of the lines are meant to be used for later versions. At least that's my guess.

2) Critter 0.90 engine (UCI protocol) - 3045 CCRL. Full strength only.

Download link:  http://www.mediafire.com/file/syg0g65cj56d7g3/Critter_0.90.zip

3) Glaurung 1.2.1 engine (UCI) - 2650 CCRL. Full strength only.

Michael Reyes - "Glaurung 1.2.1 / Glaurung 2.1 - I think Glaurung is like a Junior 7 on steroids. Where Junior 7 failed in strength, Glaurung delivered."

Download link:  http://kirr.homeunix.org/chess/engines/Jim%20Ablett/GLAURUNG/ARCHIVE/old_glaurungs_ja.zip
or http://www.superchessengine.com/glaurung.htm

4) Glaurung 2.1 engine (UCI) - 2780 CCRL. Full strength only.

Download link:  http://kirr.homeunix.org/chess/engines/Jim%20Ablett/GLAURUNG/ARCHIVE/

5) Gothmog 1.0 beta 10 engine (UCI) - 2509 RWBC Anthology list. Full strength only.

Alexander Schmidt - "Gothmog plays for sure the most interesting sacrifices. Not like the modern engines because of long extensions, it plays real sacs due to it's evaluation, not only at the kingside, also on the queenside. I remember a positional rook vs. knight sac on c3 as black in a sicilian game where such sacs are common for human players. The only advantage of this sac is a weak pawn structure. It was on the edge but Gothmog even won that game."

Download link:  http://www.rwbc-chess.de/download.htm

6) Phalanx XXII or XXIII engine (WB) - 2355 to 2376 CCRL. Has weakened levels! No config file, all commands are from the command line.

(Tony Thomas wrote: Phalanx XII (king attacks))
Tord Romstad replies, "Yes! Phalanx is my candidate for the best (not the strongest) chess program ever, and is second only to Crafty as the most influential chess program ever. Not only is it very strong and has an awesome attacking style, it was also one of the first high-quality open source programs, back in the dark ages where most programmers preferred to keep their tricks secret and progress was abysmally slow. It managed to be about as strong as contemporary versions of Crafty, while being easier to read than TSCP. It is packed with ideas which are interesting even today, eight years after the release of the last version.'

'Phalanx was the program that taught me most of what I know about chess programming, and those who look carefully will see that there are still some clear influences from Phalanx in my current source code."

Download links:

Link to regular versions 15 through 22 (WB):  http://wbec-ridderkerk.nl/html/details1/Phalanx.html

Link to Ablett's compile of Phalanx Reborn XXII JA (WB):  http://kirr.homeunix.org/chess/engines/Jim%20Ablett/PHALANX/ARCHIVE/PHALANX%20REBORN/

Link to Kirill's install of Phalanx Reborn XXII JA using WB2UCI adapter (UCI):  http://kirill-kryukov.com/chess/discussion-board/viewtopic.php?p=74553#p74553

Link to Ablett's compile of Phalanx XXIII JA (WB):  http://kirr.homeunix.org/chess/engines/Jim%20Ablett/PHALANX/ARCHIVE/

7) Quark 2.35 engine (WB) - 2430 CCRL. Full strength only.

George Tsavdaris - "yes, i find it very very aggressive"

Download link:  http://wbec-ridderkerk.nl/html/details1/Quark.html

8) Rebel 6 WB-UCI engine (WB, but can be run as UCI with use of the supplied WB2UCI adapter) - Maybe 2450 elo? Has weakened personalities!

I'm only guessing, but since a number of people liked Rebel 12's aggressiveness, maybe Rebel 6 would also be a good bet? And if the stock Rebel 6 isn't wild enough for you, it actually has a Tal personality you can try out!

Link to Rebel 6 WB-UCI:  http://www.top-5000.nl/donationware.htm

Link to a Rebel logo:  http://members.inode.at/556895/seite1.htm

9) Rebel Century (2000) WB-UCI engine (WB, but can be run as UCI with use of the supplied WB2UCI adapter) - 2550 CCRL. Has weakened personalities!

I'm only guessing, but since a number of people liked Rebel 12's aggressiveness, maybe Rebel Century would also be a good bet? And if the stock Rebel Century isn't wild enough for you, it actually has a Tal personality you can try out!

Link to Rebel Century WB-UCI:  http://www.top-5000.nl/donationware.htm

Link to a Rebel logo:  http://members.inode.at/556895/seite1.htm

10) Spark 1.0 engine (UCI) - 2920 CCRL. Full strength only.

Re: What chess engine plays the most aggressive chess vs humans:
Frank Quisinsky - "after the opening up to the "middle" of the "middlegame"
1. Stockfish 2.1.1 JA PHQ
2. Spark 1.0
3. Critter 0.9 / 1.4"

Link to Spark 1.0:  http://web.archive.org/web/20120503214636/http://members.ziggo.nl/allard.siemelink/spark/

11) Stockfish 1.6.3 engine (UCI) - 2980 CCRL. Full strength only.

Albert Silver - "The most uncompromising, wildly fun engine of the last years, IMHO, is still Stockfish 1.6.3. It had problems against other engines such as Rybka and co., but even against them, it would constantly be playing the most aggressive chess there was with pushing pawns, opening lines and active pieces."

Link to Stockfish 1.6.3 (click on "old versions" dropbox link):  http://stockfishchess.org/download/

12) Stockfish 1.7 series engines (UCI) - 3040 CCRL. Full strength only.

Re: What chess engine plays the most aggressive chess vs humans:
Albert Silver - "I'd say Stockfish 1.6/1.7. They were borderline kamikaze even against other engines. This would be my clear number one.."

Link to Stockfish 1.7 and 1.7.1 (click on "old versions" dropbox link):  http://stockfishchess.org/download/

13) Stockfish 2.1.1 JA x64 PHQ engine (UCI) - 3080 CCRL. It has reduced strength settings!

This is a standard Stockfish 2.1.1 JA x64 engine with tweaked settings. The PHQ settings are generally discussed on this Talkchess forum page: http://talkchess.com/forum/viewtopic.php?t=42091&postdays=0&postorder=asc&topic_view=&start=20
and the settings are listed in detail in News Item 006 (dated Jan 30 2012) of Frank's Chess Page, at this link:  http://www.amateurschach.de/main/_news.htm

Frank Quisinsky - "PHQ for the three musketeer ...

P = POHL, Stefan Pohl, actual status 'Expert'
H = HARTWIG, Benno Hartwig, actual status 'Expert'
Q = QuisiQuasi, means Frank Quisinsky, actual status 'sleeping pill'

This persons try out a setting, each have a good idea and the result is the most aggressive chess engine the World saw. Means PHQ is a combiantion from three good ideas in one setting."

Link to Stockfish 2.1.1 JA (click on "old versions" dropbox link):  http://stockfishchess.org/download/

14) Toga 3.1.2SE JA Chekov engine (UCI) - Probably 2900 elo? Full strength only.

This is a standard Toga 3.1.2SE JA engine with tweaked settings. The Chekov settings are listed on this Talkchess forum page:
http://talkchess.com/forum/viewtopic.php?start=0&t=21611&topic_view=flat&sid=b0d1fa3d45ed6a46afb492867435ae85

Ulysses P. - "Still the best Toga (or Fruit based engine) regarding playing style up to date. Sadly, newer Togas seem to have sacrificed style for playing strength, I won't blame them but when I can't see the difference in strength (unless I play several games and calculate an ELO) but the style is very obvious to my eyes, I'll always choose style, so I'll choose Toga 3.1.2SE JA Chekov as well."

Normally, I would send you to Kirill's mirror of Jim Ablett's engine archive for the Toga 3.1.2SE JA engine:
Direct link to Toga 3.1.2SE JA engine:  http://kirr.homeunix.org/chess/engines/Jim%20Ablett/TOGA%202/ARCHIVE/toga-312se-ja.zip

HOWEVER...this engine file is corrupt and the compressed archive will not extract. The only way I know to obtain a good engine file is this: Charles Browne discovered nine corrupt files among Ablett's archive (Toga 3.1.2SE JA is one of those) and set up a Dropbox link with good copies of the corrupt files. The bad news is that all nine files are in one download package, and it's around 40 MB. The link is listed in this Talkchess forum:  http://talkchess.com/forum/viewtopic.php?t=48973&sid=04adcc37c03050f38dd530ce6121334e

15) WChess 1.05 program (DOS) - It has weakened settings!

Another one for the retro DOS guys. The engine was designed by the revered David Kittinger. This one would also have to be run in DosBox/D-Fend Reloaded, or in a virtual Dos environment.

Michael Reyes - "WChess - back then WChess was rated as the most aggressive engine on the planet (I think somewhere around 1997-1998). I made loose backups of Computer Chess on the net before and I recall having seen a graph showing WChess as the most aggressive, while Genius the most Solid."

Note: For the WChess download from Free-Uploading.com, don't try to use any download managers. Just do a standard "Save" for this download.

Link to WChess 1.05 Dos:  http://free-uploading.com/ax9qdre55tmr/WChess_v105.zip.html

16) ZChess 2.00 London (WB) - Maybe 2400 elo? Full strength only.

Ruxy Sylwyka - "Do you need really an interesting and spectacular engine ? Here it is: http://www.fzibi.com/pharaon/zchess200.zip. Not strong like H3 but very spectacular in every game. From it you can learn how to run an attack à la manière de Tal, for example."

(Henryval wrote: I would like to see fascinating chess-games with sacrifices and brave moves.) Ruxy Sylwyka responds, "ZChess 2.00 London by Mr.Franck Zibi. By far the no.1! Nothing comparable in our galaxy ! Try it, please!"

I should add that someone found ZChess 2.22 on the internet and asked Ruxy if it was also good. Ruxy responded,

"ZChess 2.22 and ZChess 2.00 (London) have the same author and name. Here the similarities stop.

ZChess 2.22 is a normal chess engine.

ZChess 2.00 is a fantastic chess engine. ALL the old fans of computer chess know that every chess game of this engine is something like a Tal game. Every game is full of sacrificies and a spectacular chess."

Direct link to ZChess 2.00:  http://www.fzibi.com/pharaon/zchess200.zip

Search depth 8.

defense search 50%

Attack search 100%

mate search 100%

That is Tal

I forgot to  mention one thing about Rebel 12. The Windows version of Rebel 12 is no longer sold, but Ed Schröder has kindly offered the DOS version as a free download on his website. To use it, you'd have to install it in DOSBox or a virtual DOS environment.

On the same page as the DOS Rebel 12 link, Ed has also provided a link to the D-Fend Reloaded frontend/DOSBox combo. Rebel will probably run slower in DOSBox than the old days of Windows DOS. (Somewhat counteracting the slowness of DOSBox is the fact that computers are much faster these days.)

Link to Ed's Rebel 12 DOS and D-Fend Reloaded/DOSBox:  http://www.top-5000.nl/cp.htm

Thanks Escher, that took a LOT of time.  Very interesting - will check out some of those.  

So perhaps Stockfish 1.6/1.7 is the most like Tal? 

It looks like there are a number of candidates. It seems everyone has his own opinion, so who do you believe? I really have no idea.

The downside to Stockfish 1.6/1.7 is that it runs only at full strength, so you won't be winning any games against it! I sort of wonder what the Tal personality is like for Rebel 6 WB-UCI or Rebel Century (2000) WB-UCI. And then there's the Stockfish 2.1.1 JA x64 PHQ engine; I also wonder what it's like. (I also wonder how it acts at lower strength settings.)