2022-06-26

Testing old chess computers through emulation

In the days before everyone had computers, if you wanted to play chess, your only option was to play with another person. In the late 1970's Fidelity introduced a series of electronic computer chess games. These early models played rather poorly, but I knew people who bought them just to be able to play and practice whenever they wanted. I managed to borrow a few of these so that I could get a feel for how well they played.

Although the early machines did not play well, things started to improve in the 1980s. There was a golden age of dedicated chess computers that went from 1983 to about 1993.  In 1984, I purchased the Novag Super Constellation electronic chess game for what I think was $200, which was quite a bit of money in 1984. The U.S. Chess Federation had given it a rating of 2018, which is better than at least 90% of all adult tournament players. Any rating between 2000 and 2199 is considered to be the skill level of "Expert" and a higher rating of 2200 is considered to be "Master."

Although I am currently rated 2016, at the time I bought the Novag Super Constellation I was rated just a little over 1700. In a few months, I would reach a rating of 1800 which is considered to be "Class A." Nevertheless, what I remember about the Novag Super Constellation is that it played better than me, which is surprising since it only contains an 8-bit processor running at just 4 MHZ. That is not very fast compared to modern 64-bit processors with multiple cores running at gigahertz speeds.

Over time, I bought a couple of better chess-playing computers and I have fond memories of practicing with all of them. I sold all these machines when I got a desktop computer in the mid-'90s, but I kind of regret it because they all were fun to play with it.

This became an issue when I was researching these old chess-playing computers where I saw many online claims that these computers were not as good as the ratings that had been assigned to them. For example, I saw the claim that the Novag Super Constellation was only about 1750 strength, and two other computers that I owned rated 2100 and 2265 were also claimed to be weaker than their advertised ratings. None of these claims match my experience, since all of the computers played better than I did.

I was so curious about this that I wanted to get my hands on one of the old chess computers, assuming that one can be found, however unlikely, and see how it compares to my current chess ability. Fortunately, I found software that allows me to emulate dozens of old chess computers on my Windows PC.

In my first game against the emulated Novag Super Constellation on level 1, the lowest level, I was able to win by only the slimmest of margins. I tried the same thing on the Fidelity Designer 2100, a slightly better machine, and I lost. I have no doubt that the other computer I owned, the stronger Fidelity Designer 2265, would stomp me like it used to when I played it 30 years ago. I will confirm this eventually.

So I tested a variety of chess computers with a somewhat difficult chess problem..



Most serious chess players have seen this problem already and know the answer. However, if they were not familiar with it, the solution might be difficult for them to find in a real game. There is the more direct solution of 6. Nxe5 Bxd1 7. Bxf7+ Ke7 8. Nd5# (checkmate). However, for a computer to see the solution it also has to see 6... Nxe5 7. Qxh5 Nxc4 8. Qb5+ c6 9. Qxc4. There is also 7... Nf6 8. Qe2 Nxc4 9. Qxc4. Either way, that is 7 half-moves deep, which is pretty deep for ancient chess computers to look.

Based upon my testing, this is how long various chess computers take to solve this chess problem...



# Model Year Processor Speed ROM Time Depth Nodes/S
1.
Fidelity Chess Challenger 10
1978
Z80
4 MHZ
4K
Fails
2.
Fidelity Chess Challenger 7
1979
Z80
4 MHZ
4K
12 hours
3.
Novag Savant
1981
Z80
6 MHZ
24K
12:40m
4.
Novag Savant II
1982
Z80
6 MHZ
32K
12:33m
5.
Novag Constellation
1983
6502
2 MHZ
16K
6:46m
6.
Constellation 3.6 ROM set 1
1984
6502
3.6 MHZ
16K
3:30m*
7.
Constellation 3.6 ROM set 2
1986
6502
3.6 MHZ
16K
3:33m*
5 ply
8.
Novag Super Constellation
1984
6502
4 MHZ
56K
2:10m
5 ply
9.
Constellation Expert
1985
65C02
5 MHZ
64K
1:54m
5 ply
10.
Novag Forte A
1986
65C02
5 MHZ
64K
2:15m
5 ply
~1000
11.
Novag Forte B
1986
65C02
5 MHZ
64K
1:58m
5 ply
~1000
12.
Novag Super Forte
1987
65C02
5 MHZ
64K
1:13m
5 ply
~1350
13.
Novag Super Expert A
1987
65C02
5 MHZ
64K
1:00m
5 ply
~1100
14.
Novag Super Forte B
1989
65C02
5 MHZ
64K
30s
5 ply
~1400
15.
Novag Super Expert B
1989
65C02
5 MHZ
64K
19s
5 ply
~1375
16.
Novag Super Forte C
1990
65C02
5 MHZ
64K
11s
5 ply
~1500
17.
Novag Super Nova
1990
HD6301Y
4 MHZ
32KK
10s
4 ply
18.
Novag Super Expert C
1990
65C02
5 MHZ
64K
6s
5 ply
~1050
19.
Novag Scorpio 68000
1990
68000
16 MHZ
98K
9s
20.
Novag Diablo 68000
1990
68000
16 MHZ
98K
9s
21.
Fidelity Excellence
1985
65C02
3 MHZ
16K
2:16m
5 ply
22.
Fidelity Excellence
1985
65C02
4 MHZ
16K
2:00m
5 ply
23.
Fidelity Designer Display 2000
1989
65C02
3 MHZ
32K
1:45m
5 ply
~81
24.
Fidelity Par Excellence
1986
65C02
5 MHZ
32K
1:22m
5 ply
25.
Fidelity Designer Display 2100
1988
65C02
6 MHZ
64K
54s
5 ply
~180
26.
Fidelity Designer Display 2265
1989
68000
16 MHZ
64K
5s
3 ply
27.
Fidelity Designer Display 2325
1991
68020
20 MHZ
64K
3s
4 ply
28.
Chessmaster NES
1990
6502
1.79 MHZ
48K
7:00m
5 ply
29.
Chessmaster Super Nintendo
1991
65816
3.58 MHZ
110K
4:43m
5 ply
30.
Chessmaster 2000 (DOS)
1986
?
?
NA
1:33m
31.
Chessmaster 3000 (DOS)
1991
?
?
NA
4s
4 ply
32.
Stockfish 14.1 2017-iMac
2022
i5
3.4 GHZ One Core
NA
<1s
<12 ply
~880,000

It is noteworthy that the Super Constellation solved the problem in roughly 2 minutes, which is within tournament time controls. I am disappointed in Chessmaster on the Super Nintendo because it failed to achieve this. It is running on a similar processor, and it is a port of Chessmaster 2000 written by Dave Kittinger, who also wrote the Super Constellation program!

* The second version of the Constellation 3.6 solves this problem on its top two tournament levels, but the first version moves too quickly to see the answer.  It can only solve the problem on its infinite level, even though it takes about the same amount of time to see the solution. The second ROM set is based upon the Novag Expert program.

Super Constellation game #1.

2022-06-18

Puzzle Leaderboard - Chess Rankings - Chess.com

https://www.chess.com/leaderboard/tactics?page=171

I'm #8540 on the chess.com puzzle ratings.  I was expecting that the top ratings would not go too high, but I was wrong.   The top three ratings are all 65540, which for the reasons I give below, I suspect is the highest possible rating.


I find this 65540 number suspicious because the top three ratings are this number.  The maximum value that can be stored by a 16-bit number is 65536.   If you want to save storage space, why use a 32-bit or a 64-bit number to store ratings when a 16-bit number would do?  The 65540 number almost fits.  You can make it fit by making the lowest possible rating the number 5.  Why would you set a lower limit on the rating?  To not accidentally run into a divide by zero problem, which can crash computer code, or other mathematical oddities from having a low or negative number in your equation.



Chess Puzzle Rating



I reached a milestone on chess.com by reaching a 3000 rating for solving chess puzzles. The site's puzzle rating has little to do with real chess ratings because the puzzle ratings are comparatively inflated. I have seen average club players reach puzzle ratings of 2000 or 2100.

Nevertheless, reaching 3000 took a great deal of effort.

The site presents chess problems that have difficulty proportional to your current puzzle rating. I have reached a point where I am almost as likely to fail as I am to succeed. I find that I am not analyzing as well as I should so I am trying to make myself focus deeper. The casual puzzle solver will look for what the "trick" is in the position and make a move without thinking about it too hard. However, I can no longer just make cursory judgments.

A chess master in Salt Lake City that I know has been in the 3070 to 3100 range. I would like to catch up with him.

--
Best wishes,

John Coffey

http://www.entertainmentjourney.com

2022-06-06

Stockfish 15 vs. Stockfish 14.1

Overnight I did an engine versus engine match of 100 speed-chess (4+2) games.

There were 94 draws.

Stockfish 14.1 won 1.

Stockfish 15 won 5 with a score of 52%.  Its performance rating was 16 points better than Stockfish 14.1.  This website is claiming a 36 point improvement:  https://stockfishchess.org/blog/2022/stockfish-15/

Either way, the improvement is not very significant.

My computer seemed to hang while doing deep analysis with Stockfish 15.  I'm going to try again.  For the moment I am still using Stockfish 14.1.

--

2022-04-23

Chessle

I had not seen this puzzle before. I like it. It is obviously a chess spin on Wordle, which I also like.

The goal is to guess the sequence of opening movies.

https://jackli.gg/chessle/


The puzzle gives you the option to guess 3 or 5 moves.  In today's puzzle, I got the 3 move sequence on the second try.  It is an opening sequence that I like to play.





2022-04-16

Magnus Carlsen BLUFFS with Raising $100,000 When He Has 0% CHANCE to Win

Not really interested in poker, but it is interesting to see Magnus Carlsen play it and bluff.  I didn't understand why he had a zero chance of winning?  Was it because his opponent had five of a kind?

https://youtu.be/nbPTZP5tkNc

It would drive me crazy not knowing what my opponent has.  I would have to play the odds, but if I always did that then I would be predictable.

Best wishes,

John Coffey

2022-03-29

Greenwood Chess Club: White to play

https://greenwoodchessclub.blogspot.com/2022/03/white-to-play.html

I had the hardest time with this one. For those who understand king and pawn endgames, it seems counterintuitive, I think because normally the king is supposed to be in front of the pawn that he is trying to queen. Maybe it is just me.

2022-03-23

Re: Sergey Karjakin BANNED From Chess...

I support free speech.  I don't have to agree with Karjakin and he doesn't have to agree with me, because it has nothing to do with his ability to play chess.

On Wed, Mar 23, 2022 at 10:13 PM Albert wrote:
I know banning Karjakin from playing in FIDE events is currently for 6 months. I don't like that he will be unable to play in the candidates tournament. Organizations who set up international events should not be involved with politics. After all, isn't this the 21st century?

On Wed, Mar 23, 2022 at 9:00 PM John Coffey <john2001plus@gmail.com> wrote:
The first couple of games are really interesting.

https://www.youtube.com/watch?v=dieM4IDbJsQ


Sergey Karjakin BANNED From Chess...

The first couple of games are really interesting.

https://www.youtube.com/watch?v=dieM4IDbJsQ

2022-03-11

Lost chess endgame.

This is an interesting endgame that I should have lost.  My 31... Ra6 is a serious miscalculation.  I soon started to think that I was going to lose.


White can win with 34. h4 or 34. Ke1 or Ke2, but he pushes the wrong pawn making it equal.  My 36... Kc6?? is also a blunder because it takes my king out of the range of his kingside pawns.  His 39. g4 loses for a surprising reason reminiscent of the movie "Searching for Bobby Fischer."  What surprises me is that he has to abandon his pawn to draw, i.e. 39. Kb2 Kxc4 40. g4 draws.

I'm aware that I could have played the opening a little better.

[Event "Casual G/10"]
[Site "Columbus Chess Club"]
[Date "2022.03.10"]
[Round "1"]
[White "Bill Starr"]
[Black "John Coffey"]
[Result "0-1"]
[ECO "B22"]
[PlyCount "94"]

1. e4 c5 2. Nf3 Nc6 3. c3 d5 4. d4 dxe4 5. Ne5 Nxe5 6. dxe5 Qxd1+ 7. Kxd1 Bg4+
8. Be2 Bxe2+ 9. Kxe2 O-O-O 10. Be3 e6 11. Nd2 f5 12. exf6 Nxf6 13. Bg5 Be7 14.
Bxf6 gxf6 15. Nxe4 Rhg8 16. g3 f5 17. Nd2 e5 18. c4 e4 19. f3 Bf6 20. Rab1
exf3+ 21. Nxf3 Rge8+ 22. Kf2 Bd4+ 23. Nxd4 Rxd4 24. Rhe1 Rd2+ 25. Kg1 Rxe1+ 26.
Rxe1 Rxb2 27. Re5 Rxa2 28. Rxc5+ Kd7 29. Rxf5 h6 30. Rf7+ Kc8 31. Rf6 Ra6 32.
Rxa6 bxa6 33. Kf1 Kd7 34. h4 a5 35. Ke1 h5 36. Kd1 Kc6 37. Kc2 Kc5 38. Kc3 a4
39. g4 hxg4 40. h5 g3 41. h6 g2 42. h7 g1=Q 43. h8=Q Qa1+ 44. Kc2 Qxh8 45. Kb1
Qc3 46. Ka2 a3 47. Kb1 Qb2# 0-1


2022-03-10

Chess game

[Event "Casual G/10"]
[Site "Columbus Chess Club"]
[Date "Mar 10, 2022"]
[Round "2"]
[White "John Coffey"]
[Black "John Tasca"]
[Result "1-0"]

1. Nf3 d5 2. d4 Nf6 3. c4 e6 4. Nc3 c5 5. cxd5 cxd4 6. Qxd4?! exd5 7. Bg5 Be6 8.
e4 Nc6 9. Bb5 Be7 10. e5 Nd7 11. Bxc6 bxc6 12. Bxe7 Qxe7 13. O-O O-O 14. Rfe1
Rfc8 15. b4 a6 16. Rac1 Rc7 17. Na4 Rb8 18. Nc5 Nxc5 19. Rxc5 Qd7 20. Rec1 Bg4
21. Nd2 Kf8 22. Nb3 Qe8 23. Na5 Bd7 24. Qc3 Rbc8 25. a4 h6 26. b5 axb5 27. axb5
1-0 eventually