Chess Challenger 1 (close)
The notation on the Chess Challenger 1 differs from the usual chess notation. The ranks (rows) are named a - h and the files (columns) 1 through 8.
This means that the king pawn opening move (normally e2 e4) must be entered as 5b 5d (see dotted line in picture).
The warranty stated that by sending the computer and 75 dollars to Fidelity after 1 June 1977 buyers could trade it in for a better program (in fact Chess Challenger 3). Many owners sent their Chess Challenger 1 back to the factory. That's one reason why so few of them are left.
