I took Juergen Buchmueller's F8 emulator code from an old MESS version and kludged some I/O support into it so I could enter button presses and see the LED output.
I've played a couple of games and it seems to work fine.  I also added a command to look at RAM, and found that it uses 64 bytes for the current state of the chess
board.  I added another command to dump the board to the console window so you can use that as a display while playing.

This definitely isn't the right way to implement the game in MESS, but it did help me find an error in my component tracing, so I've attached an updated spreadsheet
(I think the only change is segments B and D were switched).  It also helped me figure out quite a bit more about the code, so I updated the source code as well.
The emulator flags every byte of ROM as to how it was accessed- opcode, argument, or data.  When you quit, it dumps a coverage map.  I used something similar to find
the Easter eggs in Channel F carts - if you play long enough, you should hit every byte as either code or data.  Unused areas indicate code or data that weren't hit,
which might be an Easter egg.  Unfortunately I haven't found one yet- I think that would be pretty cool.  I also dumped RAM as displayed on the LEDs so I could look
for hidden messages, but didn't see any.  There could still be some, either encrypted or stored so that they can't be easily seen.

I found a manual for a Radio Shack chess computer that is obviously very similar.  It has instructions for all the buttons.
