In the Australian and modern American rules there is a strong emphasis on collecting Limit and Special hands: the restriction on the number of allowed Chows, prohibition of mixed suits, introduction of jokers, and dozens of special hands encourage players to collect exceptional hands rather than trying to go out early on easy hands.
Some players even require that the winning hand must be a Limit or a Special hand.
To specify Limit/Special hand requirement on the winning hand:
Note: Four Winds does not prohibit you from collecting a non-Limit or non-special hand, but you cannot go out on such a hand. Declaring Out on a hand which does not meet the requirements specified is considered a faulty declaration of Out, and the normal penalties are applied.
Related topics:
Maximum number of Chows
Minimum points or doubles/faan/han
Prohibition of mixed suits
Exceptions