Can I use dice or cards to indicate my throw in Rock-Paper-Scissors?
You may not use dice to indicate your choice, as it is too easy to manipulate the dice while it is covered. The requirements for R-P-S cards are that they must have identical backs, that they clearly say "Rock" or "Paper" or "Scissors" on the front and that all themes on the cards be appropriate for a Pokemon Event as determined by the Head Judge.
Source: PUI Rules Team (2008-10-16)

Relevant cards

Note: All applicable cards may not be listed below.
BW11_56