| 1 | p.boxed |
| 2 | | Each side has two kings. Mate any of them. |
| 3 | |
| 4 | p. |
| 5 | Both kings can be checked and mated. This adds a new option to win a game, |
| 6 | by attaking both kings at the same time, as illustrated below. |
| 7 | |
| 8 | figure.diagram-container |
| 9 | .diagram |
| 10 | | fen:6KK/8/2Q5/8/8/5k2/2k5/8: |
| 11 | figcaption Both black kings are in check: white wins. |
| 12 | |
| 13 | h3 Special moves |
| 14 | |
| 15 | p. |
| 16 | A pawn can promote into a king, which can be mated too. |
| 17 | Probably not useful in a real game, but interesting for problems. |
| 18 | |
| 19 | p. |
| 20 | You can castle with any king and rook, under the same conditions |
| 21 | as orthodox castling. However, castling long is possible only with one king. |
| 22 | |
| 23 | p. |
| 24 | Note: to castle in a game you need to select |
| 25 | the king or queen first, and then move it to a rook. |
| 26 | |
| 27 | h3 Source |
| 28 | |
| 29 | p |
| 30 | a(href="https://greenchess.net/rules.php?v=dual") Dual Chess |
| 31 | | on greenchess.net. Probably invented by the webmaster Uray M. János, |
| 32 | | inspired by Coregal chess from chessvariants.com. |