3 Card Blind is a fascinating Magic the Gathering format where everything happens at the deckbuilding phase — players never actually play their games.
In 3 Card Blind, players construct a 3-card opening hand with no deck nor sideboard. Game results are determined in a best-of-two format (each player goes first once) where each player is assumed to play perfect game with perfect information.
From the website:
3-Card Blind is an unusual MTG format where each player has a 3 card opening hand and no deck or sideboard.
Players submit decks but do not actually play games; games are played “automatically” under the assumption that both players have perfect information and will only make decisions that will lead to a win (or a tie in the case where a win is not possible).
All decks submitted during a play period play against all other decks submitted during the same play period (each deck plays against each other deck twice, one game where player A goes first and another where player B goes first).
The format will test your deck building capabilities as well as your ability to adapt to and predict the meta. Please note: you still must pay for casting costs on cards as usual, so consider including 0 cost cards, a land, or cards with alternative casting costs.
In the tournaments being run by the people running the website, they have a group of people who manually go through every matchup of submitted decks to determine the outcome.
Essentially, 3 Card Blind matches are puzzles and quizzes of game rules knowledge.
You can learn more about it from the format’s website and this introductory video. Their Youtube channel has a lot of examples that you can use to see if you could figure out the right outcomes of matches. And contrary to usual Youtube comment sections, these puzzle videos’ comment sections are actually worth reading because there’s usually a lot of great discussion about rules and strategies — helpful even if you play regular Magic and not 3 Card Blind.
And no, you can’t play Thassa’s Oracle and win every game — it’s been permabanned from day 1.