The Homecoming Theme

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:

'First Homecoming B' refers to the first WB uncaptured.
'Unpromoting N' refers to the BN that is uncaptured as the First Homecoming B is closed in after its return home.
'Homecoming RP' refers to the BRP (which, earlier in the retroplay, is the uncaptured Unpromoting N) that retracts to a7 or h7.
'Homecoming Corner' refers to the SW corner if the First Homecoming B is the WKB, or the SE corner if the First Homecoming B is the WQB.
'Second Homecoming B' refers to the WB that originated in the Homecoming Corner.
'Homecoming R' refers to the WR that originated in the Homecoming Corner.
'Third Homecoming B' refers to the BB uncaptured as the WQ, the Second Homecoming B, the Homecoming R, and the WK are closed in after returning to their respective home squares.
'Locking P' refers to the WP on the seventh rank that prevents lateral retroplay by the BK until after the return of the Third Homecoming B.

The thematic retroplay has the following features:

Black uncaptures the First Homecoming B.
The First Homecoming B retracts home and White uncaptures the Unpromoting N. (No other uncapture will work.)
The WK must retract to the extreme square (a1 or h1, as the case may be) of the Homecoming Corner.
The Unpromoting N unpromotes to become the Homecoming RP, which uncaptures the Homecoming R.
W uncastles in the Homecoming Corner.
The Homecoming RP uncaptures the WQ and the Second Homecoming B. (Those two uncaptures are the only thematic ones whose order can be interchanged.)
The WQ and the Second Homecoming B return to their respective home squares, as the Homecoming RP retracts to its home square.
The uncapture of the Third Homecoming B locks the WQ and the Second Homecoming B in the Homecoming Corner, along with the WK and the Homecoming R (which had earlier returned home by uncastling).
The Third Homecoming B retracts to its home square, permitting the retraction of the BP that blocks the Locking P.
The Locking P uncaptures a BR (QR if Homecoming Corner is Q side, KR if Homecoming Corner is K side).

The following four compositions address the theme:

1 - Niels Høeg
Magasinet 11/1, 1942 (January 11^th?)
Nytårshilsen

[2k5/1pPp1pp1/3p4/3p2p1/8/2P5/PPP1PPP1/K2n1B2]

10+9. Retract 13.0 moves (White starting) then H#1

2 - H. Goldsteen
Die Schwalbe, 1988

[2k5/1pPp1pp1/3p4/1K6/4p1p1/4PP2/PPP2PP1/8]

9+8. May White move?

3 - H. Goldsteen
Probleemblad, 1989

[N1k1N3/1pPp2p1/3p1pK1/8/2Pp4/5P2/PPP2PP1/7b]

11+8. White mates in one

4 - Thomas Volet
Internet retros-list, Feb. 1997

[3N1k2/1p2pPp1/4p3/Kp2p3/2p5/2PP4/1PP2PPP/8]

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.