We love our pups!! Misu, RIP 28 Nov 2010. Tikka, RIP 11 Aug 2011.
And yes, it's in the rulebook on page 6:
the rulebook (emphasis mine) wrote:
6. Requirement: Any requirement must be met in order to play the card. Some cards require a global parameter to have reached a certain level, while others can only be played while the parameter is still low (see example card). Some cards require that you have certain tags or production. (Note: In order to play the card you must also be able to perform the e ects of the card, see page 9.) Note also that the requirement only needs to be fulfilled when playing the card, not when you use it later.