Many variants of Shogi have been developed over the centuries, ranging from some of the largest Chess-type games ever played to some of the smallest. A few of these variants are still regularly played, though none are nearly as popular as Shogi itself. It should be noted that the drop rule, often considered the most notable feature of Shogi, is absent from most Shogi variants, which therefore play more like other forms of Chess, with the board becoming less crowded as pieces are exchanged.