Price of Knowledge — ruling 1

Count the number of cards in that opponent’s hand when the ability resolves to determine how much damage is dealt.

Price of Knowledge : règles, fonctionnement et interactions (MTG)

Price of Knowledge is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Players have no maximum hand size. At the beginning of each opponent's upkeep, this enchantment deals damage to that player equal to the number of cards in that player's hand.

How it works : Price of Knowledge

Original English text — Wizards of the Coast / Scryfall

#1October 17, 2013· Wizards of the Coast
Count the number of cards in that opponent’s hand when the ability resolves to determine how much damage is dealt.
No other card is named in this ruling.