Attacks and isn't blocked

An card ability that triggers when a creature “attacks and isn’t blocked” triggers when the creature becomes an unblocked attacking creature. It usually receives a bonus under this condition.

History

The first card with this ability appeared in Arabian Nights: Merchant Ship (Whenever this creature attacks and isn’t blocked, you gain 2 life). It later became a recurring mechanic in Fallen Empires, the Ice Age block and the Mirage block. After Judgement it was only used as a cameo mechanic. It was repeatedly used for flavor reasons on Universes Beyond cards.

Ninjutsu, introduced in Betrayers of Kamigawa is a major keyword ability that can be activated when a creature attacks and isn't blocked.

Rules

From the glossary of the Comprehensive Rules (July 25, 2025—Edge of Eternities)

Attacks and Isn’t Blocked

An ability that triggers when a creature “attacks and isn’t blocked” triggers when the creature becomes an unblocked attacking creature. See rule 509.1h.