Mystic Mine: the player with more monsters is shut down

Card text

If your opponent controls more monsters than you do, your opponent cannot activate monster effects or declare an attack. If you control more monsters than your opponent does, you cannot activate monster effects or declare an attack. Once per turn, during the End Phase, if both players control the same number of monsters: Destroy this card.

Property

Field

Explained

What it does

A Field Spell. If your opponent controls more monsters than you, they can't activate monster effects or declare attacks. If you control more, you can't. In the End Phase, if both players control the same number of monsters, it's destroyed.

Play it when

It can't be used in Advanced Format; it's Forbidden in the TCG.

Common mistakes

Forgetting it also locks you if you control more monsters.

How it works

Status: Forbidden in the TCG (Sept 21, 2026 list), so it can’t be used in Advanced Format.

Mystic Mine is a Field Spell.

If your opponent controls more monsters than you, your opponent can’t activate monster effects or declare an attack.
If you control more monsters than your opponent, you can’t activate monster effects or declare an attack.
Once per turn, during the End Phase, if both players control the same number of monsters: destroy this card.

Rulings in plain English

Locks: Neither starts a Chain.

Self-destruct: Mandatory, in either player’s End Phase, whenever both players have the same number of monsters. It does start a Chain and doesn’t target.