When can actions be played and not played?

Based on the rules of Riftbound, the ability to play Action cards depends on the state of the game (Open vs. Closed) and whether you have "focus" during a showdown.

When Actions CAN be played:

1. During your turn in a Neutral Open State: When no chain exists, you may play actions freely as part of your turn (Rule 309.2, 398.1.a).
2. During a Showdown (if you have focus and the chain is empty): If you have focus during a showdown, you may play an action to start a new chain, provided no other effects are currently on the chain (Rule 309.2, FAQ).
3. Cards with the "Action" keyword: If a card has the Action keyword, it grants permission to be played during showdowns on any player's turn, provided the chain is empty and you have focus (Rule 732.1.b).

When Actions CANNOT be played:

1. During a Closed State (when a chain exists): Once a chain has been started (by an action or a triggered ability), the game enters a "Closed State." You cannot play actions while a chain is active; you may only play Reactions (Rule 309.1, 309.1.a).
2. In response to an opponent's action: You cannot respond to an opponent's action card with your own action card. Once an action is played, it creates a chain, which immediately closes the state and restricts further play to reactions only (FAQ).
3. When you do not have focus: During a showdown, even if the chain is empty, you cannot play an action unless you currently hold "focus" (FAQ).

Summary of Key Concepts:

• Open State (No chain): Actions and Reactions can be played.
• Closed State (Chain exists): Only Reactions can be played.
• Focus: Required to start a new chain with an action during a showdown.
• Action Keyword: Specifically grants permission to play a card during showdowns on any turn, but it does not bypass the restriction that the chain must be empty to play an action.

Note: This ruling is based on the provided game rules and FAQs. If you have a specific card interaction in mind, please provide the card names so I can verify if they have unique properties.