How many cards must a standard Yu-Gi-Oh! deck contain, at minimum?

How to get close to this number

Anchor on the card games you know. Deck minimums across the major trading card games cluster in a narrow band, because the same design problem produces the same answer: a deck has to be small enough that a strategy is reliable and large enough that it cannot be reduced to a single combination. That band is a few dozen cards, and this game sits at the low end of it.

The strategic consequence in the explanation is the interesting part and it runs opposite to intuition. A minimum is usually treated as a floor to be exceeded; here competitive players build exactly to it, because a smaller deck raises the probability of drawing the specific cards a combo needs. When consistency matters more than variety, the minimum is the optimum.

Note what the count excludes. The main deck is one of several zones, and extra and side decks are governed by their own limits, so a tournament-legal collection of cards is larger than this figure suggests. Rules also differ between the Japanese and international versions of the game, which is why the question names the official card game rules specifically.