Wizard on trump card trick

[_Nero]

Hi,
Had a debate with a friend while playing about the following rule (which a didn't notice) :

Wizards are Trump, however, they need not be played when the first card of a trick is an actual Trump color card.

Does that mean that we can not play wizard when a player opens with a trump card ?

[aesche]

Rules for trumps dont apply on white (wizards and fools) cards. They stand above/below everything, and can be played (or not be played) whenever you want.