This tape is labeled:

Processor Technology; 8080 Chess Cassette; P/N 727152

It contains:

CHESS    0000 16F9
END      CC00 0000

A middle of the road chess program at the time.  Good for their first effort. 
 It out performed all the other chess programs I had for the Sol (I never got 
any of the CP/M ones) but Zargon ran circles around PTs chess.  It always 
made a move on level 3 but if it was raised to level 4 and the board became 
complicated, it would get stuck in an infinite loop (the stack would wrap 
around itself).