Do cards with hidden only gain reaction speed when they are played facedown or can they also be played at reaction speed from hand?

Question

Accepted Answer

Cards with the **Hidden** keyword can only be played at **Reaction** speed *after* they have been hidden facedown on a battlefield. They cannot be played at Reaction speed directly from your hand.

According to **Rule 811.1.b**, the **Hidden** keyword functions as follows:

> "While this card is in your hand or in your Champion Zone on your turn during an Open State, you may pay [A] to hide this facedown at a battlefield you control... **Beginning on the next turn, this gains [Reaction] and you may play this, ignoring its base cost.**"

To summarize:
*   **From your hand:** The card must first be played using the "Hide" action (which costs [A]) to place it facedown on a battlefield. This action is performed during an Open State on your turn.
*   **From the battlefield (facedown):** Beginning on the next turn after it was hidden, the card gains the **Reaction** keyword, which allows you to play it at Reaction speed.

Essentially, **Hidden** is a setup mechanic that requires you to place the card on the board before it gains the ability to be played at Reaction speed on a later turn.