advantage. Castling in chess variants Variants of Western chess often include castling in their rule sets, sometimes in a modified form. In variants played on a standard 8×8 board, castling is often the same as in standard chess. This includes variants that replace the king with a different royal piece, as is the case with the knight in Knightmate. Some variants, however, have different rules; for example, in Chess960, the king may move more or fewer than two squares (including none) while castling, depending on the starting position. Castling can also be adapted to variants with different board sizes and shapes. Some such variants, like Capablanca chess (10×8) or chess on a really big board (16×16), preserve the castling movement of the rooks, meaning that the king moves a different distance along the . Conversely, other games, like Dragonfly (7×7), specify that the king still castles two squares in each direction, and the rook is the piece that moves differently. In a few variants, most notably Wildebeest chess (11×10), the player may choose to move the king any distance and move the rook accordingly. Castling sometimes features in chess variants not played on a square grid, such as masonic chess, triangular chess, Shafran's and Brusky's hexagonal chess, and millennium 3D chess. In 5D Chess with Multiverse Time Travel, castling is possible within the spatial dimensions but not across time or between timelines. Some chess variants do not feature castling, such as losing chess, where the king is not royal, and Grand Chess, where the rooks have significantly more opening mobility. In a handicap game with rook odds, the player giving odds may castle with the absent rook, moving only the king. Chess without castling Writing in 2019, former world chess champion Vladimir Kramnik proposed a variant of chess without castling. This variant would reduce king safety, theoretically leading to more dynamic games, as it would be considerably harder to force a draw and the pieces would be forced to engage in a mêlée. In 2021, former world champion Viswanathan Anand defeated Kramnik 2½–1½ in a no-castling exhibition match under classical time controls. Castling in chess problems Castling features in some chess problems. The earliest known study containing castling was published in 1843 by Julius Mendheim. Retrograde analysis Castling is common in retrograde analysis problems. By chess problem convention, if a player's king and rook are on their original squares, the