Can You Solve This Crazy Puzzle?

John Coffey
0 seconds ago
I thought the first mate-in-25 moves problem would be too deep for Stockfish 15 to find, but it finds it immediately.  I am somewhat familiar with chess-playing algorithms, and I assumed that the search tree would grow exponentially toward infinity, but it helps that all the wrong choices get White mated quickly.


Chess Puzzle

I really like this chess problem.  I was stumped, but it is simple enough that I should have been able to figure it out.



Loss to Novag Super Constellation level 1

Back in 1984, the Novag Super Constellation chess-playing computer was one of my favorite possessions.  I doubt that many of these machines would still be working because the model is almost 40 years old and old capacitors tend to go bad given enough use.   

In 1984 the USCF gave the Novag Super Constellation a rating of 2018 which has been somewhat controversial.   Most online sites today claim that its actual strength is in the 1700s, which I don't believe.  I remember it being much better than me and I was rated in the 1700s at the time.

There was a golden age of chess-playing computers that went from about 1982 to 1995 before most people owned a PC and the only way to play chess against a computer was to buy one of these devices.  Once people bought computers, the market for chess-playing computers almost completely disappeared, although recently there has been a bit of a resurgence of chess-playing computers.  Also, playing chess on mobile devices has become very popular.

Since I am curious about everything, I have wondered for years how I would fair against the Novag Super Constellation today because I am now rated much higher.  I even considered trying to buy an old chess-playing computer on eBay, although not necessarily this model because there are much better ones that came out later.

Recently I found a way to play the Novag Super Constellation using emulation on my computer.  Although I did beat level 1 once, I have lost a few games too.  I'm not quite comfortable playing the simulated chess machine because graphically it is not as nice as playing a modern chess program, plus you have to move the computer pieces as if you were playing the real chess computer which is slightly distracting.

The computer proves that it does not miss tactics on level 1 where it averages 5 seconds per move, which is speed chess.  I think that it would crush most Class A players at speed chess.  This is impressive for an 8-bit 6502 processor running at just 4 MHZ.  It shows that you don't need much computing power to see 3 moves ahead, which is maybe enough to outplay or equal average tournament players even at tournament time controls.

I have set up positions to test the device, and I found that its playing strength only improves marginally as you give it more time.  The Novag Super Constellation seems to be optimized for 5 seconds per move and it plays pretty strong at that level.  One reason is that it has a very good opening book allowing it to reach strong positions out of the opening.

In this game, Stockfish analysis agrees with my opening moves up to move 12.  By move 20 it thinks that I am positionally crushing it, but it is not clear to me at all why it thinks that I am 4 pawns ahead.  I need to do more analysis.  On move 21, I blundered, unfortunately.  If I can avoid making these kinds of obvious tactical mistakes then I likely would beat the machine on level 1.  Once I fell behind, the computer showed no mercy and proceeded to crush me.

[Event "CB-Emu"]
[Site "?"]
[Date "2022.10.16"]
[Round "1"]
[White "Coffey, John"]
[Black "Novag Super-Constellation Lv1"]
[Result "0-1"]
[ECO "E18"]
[WhiteElo "2016"]
[BlackElo "2018"]
[Annotator "Stockfish 14.1"]
[PlyCount "62"]
[EventDate "2022.10.16"]

1. Nf3 Nf6 2. d4 e6 3. c4 b6 4. g3 Bb7 5. Bg2 Bb4+ 6. Bd2 Be7 7. O-O O-O 8.
Nc3 d5 9. cxd5 exd5 10. Bf4 c5 11. Rc1 Nc6 12. dxc5 {
Stockfish agrees with all my opening moves.} Bxc5 13. Bg5 ({Better is}
13. a3 {and White has a winning advantage.}) 13... d4 14. Ne4 Qe7 15.
Nxf6+ ({Better is} 15. Nh4) 15... gxf6 16. Bh6 ({Better is} 16. Bh4)
16... Rfe8 17. Re1 ({Stockfish 14.1:} 17. Nh4 {Now not} Qxe2 18. b4
Nxb4 (18... Bxb4 19. Bxc6) 19. Bxb7) ({Not} 17. b4 Nxb4) 17... Rac8 ({
Black can do much better with} 17... Rad8) 18. a3 Qd7 19. b4 Bf8 20. Qd2
Ne5 21. Nxd4?? {Here I blunder away a winning game.  The antique
chess computer has no problem seeing shallow tactics even on level 1.  To my
defense, I'm not quite comfortable visually playing on the simulated chess
computer.} ({Stockfish 14.1:} 21. Nxe5 Rxe5 22. Bf4 {And White is winning.})
21... Bxh6 22. Qxh6 Bxg2 23. Red1? ({Stockfish likes} 23. Qxf6 Qxd4 (
23... Bb7 {loses to} 24. Nf5) 24. Kxg2) 23... Ng4 24. Qf4 Rxc1 25. Rxc1 Re4 {
The computer proves how tactically strong it is.  I am sure it would beat most
A players at speed chess.} 26. Qb8+ Kg7 27. Rc8 Nh6 {
Shutting down any hope for White.} 28. e3? ({White can do better with}
28. Rd8 Qh3 29. Qc8 Qxc8 30. Rxc8) 28... Qh3? {
Stockfish thinks this is a blunder and prefers Bh3, but it hardly matters.}
29. Qb7? {A blunder.} ({Stockfish prefers} 29. Nf5+ Qxf5 30. Kxg2) 29... Rxd4
30. Qxg2 Rd1+ 31. Qf1 Rxf1# 0-1


Don't mess with my DUCK

Duck Chess is an exciting and absorbing new chess variant invented in early 2016 by Dr Tim Paulden, the president of Exeter Chess Club (Devon, England).

The basic principle of the game is very simple: in addition to the usual pieces, the two players have joint control of a small rubber duck which acts as a "blocker" (i.e. nothing can move onto or through it), and which must be moved to a new square after every turn. The goal is to successfully capture the opponent's king.