Nicholas Gray, 14 Mar 1995
I recently came across a retrograde chess problem in a newspaper which required you to reconstruct a game which had finished after 13 moves by each player. What is the longest game which ( given the end position ) forms a retrograde problem with unique solution, the solution being the entire list of moves for the game? I don't really mean a theoretical limit, what's the best anybody's come up with?
The 1991 booklet on "Shortest proof games" by Gerd Wiltd gave a position with DUAL-FREE shortest game up to White's 58th move. The problem is by Pronkin + Frolkin, 1989.