a(href="http://www.hexenspiel.de/engl/synchronous-chess/") Synchronous chess
| , modified to allow en-passant captures
| and disable the "exchange of captures" stage.
- a(href="http://www.pion.ch/echecs/variante.php?jeu=synchro") Another description
+ a(href="http://www.pion.ch/echecs/variante.php?jeu=synchro")
+ | Another description
| (in French).