① If your opponent has 4 or more cards in their hand:
Look at their hand and shuffle 1 Monster from it into the Deck (if any).
● If playing online, you may take notes of your opponent's cards. In real-life Duels, you may not.
(This disparity is due to the nature of online play, as it's impossible to enforce note-taking:
Online, you could screenshot the cards in your opponent's hand or write them down in a notepad,
and nobody would be able to tell that you're note-taking).