Ruling number of cards in deck?

[Slowbro]

Are the number of cards in you or your opponents deck public knowledge? During a battle could I ask the opponent the number of cards in their deck? thanks

 

[King Arceus]

The number of cards in a deck I believe would be considered public knowledge. Hand size, number of prize cards, and number of cards in the Discard Pile are public knowledge.~KA

 

[Sleeping Snorlax]

To confirm. The number of cards left in either players deck is public knowledge. You may ask your opponent how many cards are left in their deck and vise versa, but only try to ask during your turn to prevent upsetting your opponent. You may also count how many cards are in your deck whenever you wish. Just don't do it to stall =/