Over time, the amount of questions involving these two cards has increased drastically, with their recent resurgence back into the competitive scene. So, I took it upon myself to combine the reliable information that we have about Psi-Blocker and Prohibition (which is a lot more difficult than I make it sound).
Last updated: 6th September, 2015
(This list is unofficial as far as the TCG goes, but I still do feel it is a useful reference. As it currently stands, we do not have any rulings from a TCG official source regarding Prohibition or Psi-Blocker. In the event this does change, any differences will be updated, but you should use the one provided by Konami before this one.)
What you can and cannot do with a card declared by Psi-Blocker:
- Normal Summon or Set
- Special Summon
- Be placed on the field
- Be used as a Fusion, Synchro, or Xyz Material Monster
- Manually change its battle position
- Activate its effects that start a Chain (including mandatory effects)
- Apply its Continuous Effects
- Activate the card, or any of its effects
- Apply any Continuous Effects
- This also includes Setting a Spell/Trap Card by the effect of Dust Tornado, Fire Fist monsters, etc.
- Playing it from the hand or Deck, such as by the effect of Masked Beast Des Gardius, Destiny Board, etc.
- Use it to pay a cost. Examples: Trade-In, Enemy Controller, Sacred Sword of Seven Stars, etc.
- Copy its name, Level, ATK, DEF, and effects. Examples: Elemental HERO Prisma, Phantom of Chaos, etc.
- Use it for other card effects. Examples: Reinforcement of the Army, Foolish Burial, etc.
- (It is perfectly legal to add it to your hand from any card location, target it, and/or affect it by any means.)
- (Exceptions: You cannot use it for anything that would perform a Fusion or Synchro Summon.)
- [Exception to exception: Future Fusion]
- Use it for another monster’s Summoning Procedure.
- (This also includes using it as part of a Tribute Summon)
- Change its battle position via card effect. Examples: A/D Changer, Book of Moon, etc.
- Apply any lingering effects
- Use it to pay a cost. Examples: Summoner Monk, etc.
- Use it for other card effects. Examples: Magician of Faith, Ninja Grandmaster Hanzo, etc.
- (It is perfectly legal to add this card to your hand from any location, or have the declared card’s effects used via another card. Example: Spellbook of the Master)
- Apply any lingering effects
General things you should know:
- Psi-Blocker can affect cards that are already on the field. This is due to a textual difference with Prohibition. Psi-Blocker does not have an equivalent to the last sentence of Prohibition.
- You can only declare cards that are legal card names in the TCG. This also extends to cards that alter their original name. Tokens cannot be declared.
- (For example, Harpie Lady 1, Harpie Lady 2, and Harpie Lady 3 cannot be declared. You must declare Harpie Lady. All three of those cards will be treated as if they are Harpie Lady.)
- You do not need to declare the full name of a card. You only need to provide enough details that both you and your opponent have a clear understanding as to which card you are referring to.
- (If you actually do declare the name of one card, when you mean another, you are bound to what you actually stated. Example: If you declare “Black Luster Soldier“, but intended for “Black Luster Soldier – Envoy of the Beginning“, “Black Luster Soldier – Envoy of the Beginning” can still be used.)