Glossary
In the thematic retroplay, i.e., the retroplay that must take place before the position unlocks (here, when the BK is free to retract), of a fully realized example of the Homecoming Theme, six uncaptured units (one a Knight that unpromotes and, as a P, accounts for three of those uncaptures), together with four units supplied in the diagram, must return permanently to their respective home squares, in the course of which the WK must retract to a corner square and subsequently uncastle. Only 18 units need appear in the diagram.
Defined terms, for simplicity of reference:
The thematic retroplay has the following features:
The following four compositions address the theme:
1 - Niels Høeg Magasinet 11/1, 1942 (January 11th?) Nytårshilsen
10+9. Retract 13.0 moves (White starting) then H#1
2 - H. Goldsteen Die Schwalbe, 1988
9+8. May White move?
3 - H. Goldsteen Probleemblad, 1989
11+8. White mates in one
4 - Thomas Volet Internet retros-list, Feb. 1997
10+8. How long must the N have remained at d8?
The Hoeg Progenitor presents the Unpromoting N in the diagram without features (1) and (2), presents feature (3) in the diagram, doesn't show feature (5), and partially displays feature (6), but nevertheless clearly anticipates the general theme. Goldsteen 1988 does not show feature (3), and partially displays feature (6). Both Goldsteen 1989 and Volet 1997 show all features (the latter without stipulation as to which color has the move).
Provided by Tom Volet, as developed through correspondence with Henrik Juel.