Many thanks for this.
I refitted the ZXpand and my second game started off ok with some good tactical play and piece capture by both sides and all was well until the 42nd move which involved zx81(black) capturing ZX80(white)kings rook with kings knight.
The ZX81 made the move but when I looked at the ZX80 monitor the ZX81 knight was being displayed as a black rook and all piece movement stopped, in other words a crash.
I can only assume the ZXpand and ZXpand ROM set-up could be at fault so tonight I will replace the ZXpand ROM with the original ZX80 ROM and use the ZX80 as an original 1k machine with no ram-pack fitted and try again.
I can post the results of the game played up to the 42nd move if you want but to give you an idea of timing it varied between 5 seconds and up to 2 minutes 20 seconds per move by the ZX80 at one point.
The ZX81 took about 2 seconds per move using ZX Chess 2 at the lowest level which I think is supposed to be 1 ply.
(30sec move as a mean should be good on ZX80/81)
Really curious to see the next game!
Thanks for Black start version. It's much better for my old eyes!
I have always preferred a white letter to mean a white piece and a black letter to mean a black piece as I find it easier to read.
I started a new game with the original 4 ply version but after about 20 moves it decided that a pawn could leap 3 squares and capture a bishop! I suspected a memory or ZXpand connection fault so I took my ZX80 apart reseated the ROM and CPU cleaned the edge connector and tried again and managed a complete game which the ZX81 won in 72 moves having promoted 2 pawns to 2 queens . I did log the moves but not the timings but the ZX81 never exceeded 2 seconds, the ZX80 averaged between 5 and 40 seconds and on one occasion 2:30 to decide if to capture opponents queen at the risk of losing its own queen.
I would add that the ZX80 stopped moving when the game was one move from mate and I manually had to make whites only move at that point to end the game.
Tonight I will try a game with the new black start and log timings,moves etc.
72 moves was not an easy win, but with such time disparity I was hoping better. Seems I should probably do something to improve pawn promotion evaluation...
Did you spot other "strange" moves? Can you post the log in the simplest way? If the structure is fixed in some way I can even make a converter to have them in PGN (if they are not already in this format) for better analysis...
Thank you for the tests!!!
Slight problem with the new black version is the king and queens are reversed if you assume white is now black.
The ZX81 has white at the bottom with the king obviously to the right of the queen and the screen cannot be reversed and relies on notational input not cursor control and because we are now saying that on the ZX80 the black pieces are now white then the king and queen needs reversing or the ranks swapping which you say cannot be done.
I have chess for the Spectrum which allows rank reversal so will try that instead as reading the chess board in reverse to accommodate the ZX81 is causing me to make mistakes.
Good you can rotate the Spectrum at least (the changes for rotation are not difficult but spread in various part of the code and so not a quick upgrade)!
It beat the ZX80 but encouragingly it too over 50 moves to do it. I will play again tonight and log the game,timings etc and post back.
The black start is still useful because as you say the logic is different and plays an interesting game.
Even with the "not mirrored" version try to play black (meaning the color at the bottom of the screen) with ZX80 against a Spectrum playing white. As said even without initial logic might play a bit better (moving pawns instead of wasting moves with the tower until something interesting happens)...
Another option might be to start from a predefined opening to play on a leveled field, since most probably anyway the spectrum has an opening book!
So yes, it was a computer chess championship winner, and is confermed that it has a opening book library.!..
ZX80 playing white, Spectrum, black.
ZX80 using 4ply 1k version and Spectrum using IS chess level 1.
All the spectrum moves were timed at about one second.
The ZX80 timings vary and are approximate.
I scanned the notes that I logged as the game progressed rather than type them out again(my eyes are very tired at the moment!) but they should be readable if not let me know and I will redo them.
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