Editing Castling (section)

===Novelty problems===
{{Chess diagram  
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|Siegfried Hornecker
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| Helpmate in three with Koko fairy condition<ref>{{cite magazine |last=Hornecker |first=Siegfried |date=9 October 2011 |title=P1204776 |trans-title= |url=https://pdb.dieschwalbe.de/P1204776 |language=German |magazine=Die Schwalbe |location= |publisher= |access-date=13 July 2022}}</ref> 
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Some joke chess problems involve castling with a promoted rook of the opponent's color. In orthodox chess, this would be illegal since the rook would be giving check to the king, but under fairy chess conditions, this might not actually be check.

The diagrammed problem involves castling with an opposing rook under the Koko fairy condition (each piece must end up adjacent to another piece when moving).<ref>{{cite web |title=Chess Problem Fairy Definitions |url=http://www.strategems.net/sections/fairy_defs.html |website=StrateGems – US Chess Problem Magazine |access-date=28 March 2022}}</ref> The solution (Black's move being given first per helpmate convention) is:
:'''1. Bg7 h8=R 2. Bf6 Kg6 3. 0-0 Kh7#'''

where, after 3.0-0, White's rook is not checking the king; a hypothetical capture of the king would result in the rook not being adjacent to any other piece, which is illegal under the Koko condition.

The allowance of castling with a "phantom rook" in handicap games has also been used in joke problems.<ref>{{Cite web |url=https://www.chesshistory.com/winter/extra/castling.html |work=Chess Notes |title=Phantom rook (games played at odds) |last=Winter |first=Edward |author-link=Edward Winter (chess historian)  }}</ref> Many other joke variations on castling are possible.
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====Vertical castling====
{{Chess diagram 
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|C. Staugaard
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| White to play and mate in two
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In 1907, C. Staugaard composed a [[Chess_problem#Types_of_problems|two-mover]] in which White promotes a pawn to a rook and then castles vertically with the newly promoted rook (placing the king on e3 and the rook on e2), since the rook has not moved. In the position on the right, White plays 1.e8=R, and after the forced move 1...Kxc2 castles vertically with the promoted rook, checkmating Black.

Vertical castling, also known as "Staugaard castling" or "Pam–Krabbé castling", has been used in a few [[joke chess problem|novelty chess problems]].<ref>{{cite web| url = https://pdb.dieschwalbe.de/search.jsp?expression=K=%27Staugaard%27| title = Staugaard castling at Die Schwalbe}}</ref><ref>{{cite web| url = https://www.yacpdb.org/#search/Ly8vLy8vLy8vLy9QYW0gS3JhYmJlIGNhc3RsaW5nLCAvLy8xLzEvMS8w/1| title = Pam-Krabbé castling at yacpdb}}</ref>

[[Tim Krabbé]]'s 1985 book ''Chess Curiosities'' includes a problem featuring vertical castling, along with an incorrect claim that the problem's 1973 publication prompted [[FIDE]] to amend the castling laws in 1974 to add the requirement that the king and rook be on the same rank. In reality, the original FIDE Laws from 1930 explicitly stated that castling must be done with a king and a rook on the same rank (''traverse'' in French).<ref>[https://fr.wikisource.org/wiki/R%C3%A8gle_du_Jeu_d%E2%80%99%C3%89checs_de_la_F._I._D._E._(%C3%A9dition_officielle_1930) ''Règle du Jeu d’Échecs de la F. I. D. E. (édition officielle 1930)''], (in French), FIDE, 1930 (via wikisource)</ref> It is unclear whether any historically published sets of rules would technically allow such a move.
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