There are two game states during the Duel, "open" and "closed".
Whenever a player performs an action, the game state is "closed". If nothing is going on, and neither player wishes to do anything, the game state is "open". Technically, this means:
- The Turn Player has the chance to activate the next fast effect
- The turn player passes to the opponent
- The opponent then passes back
- No Chain is currently being formed
The game state is "open".
If the game state is "open", the turn player may perform any of the following actions, when appropriate:
- Conduct their normal draw (during the Draw Phase)
- Normal Summon / Set
- Flip Summon
- Special Summon (That does not start a Chain)
- Change a monster's battle position
- Attempt to move to the next Phase/Step
- Declare an attack (during the Battle Step of the Battle Phase)
- Activate any card/effect of any Spell Speed.