The Regulating Authority may require the face of each card to be symmetrical (Law 1B); The backs of all 52 cards in a deck should be identical, so no card is identifiable from the back (Law 1C)
Why people argue about this
People often assume that the requirement for cards to have symmetrical faces is about aesthetics, thinking it's meant to make the decks look more pleasing or professional. However, the actual intention behind this rule is to prevent players from identifying their opponents' cards by looking at the backs of the cards, ensuring fair play and secrecy in bridge games.
