Taxation refers to hindering the opponent from doing a specific action unless he pays a sum of Mana, usually without color specification. It is primarily used on blue Counterspells such as Mana Leak. However, recently white has gained the ability to require the opponent to pay mana to attack with creatures when effects such as Propaganda was shifted into white with Windborn Muse, Cowed by Wisdom and the direct Propaganda-Mirror, Ghostly Prison. Force Spike was also directly mirrored into white as Mana Tithe.

Taxation should be distinguished from Prophecy's Rhystic mechanic even though the mechanics are related.