Brainwash — ruling 1

This ability is paid for during the declare attackers step of the combat phase.

Brainwash — ruling 2

If there are multiple combat phases during the turn, the attack cost must be paid each time if you want to attack with the creature.

Brainwash — ruling 3

Paying this cost is not an instant or any other kind of ability, it is an additional cost on the declaration of the attacker.

Brainwash : règles, fonctionnement et interactions (MTG)

Brainwash is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Enchant creature Enchanted creature can't attack unless its controller pays .

How it works : Brainwash

Original English text — Wizards of the Coast / Scryfall

#1October 4, 2004· Wizards of the Coast
This ability is paid for during the declare attackers step of the combat phase.
No other card is named in this ruling.
#2October 4, 2004· Wizards of the Coast
If there are multiple combat phases during the turn, the attack cost must be paid each time if you want to attack with the creature.
No other card is named in this ruling.
#3October 4, 2004· Wizards of the Coast
Paying this cost is not an instant or any other kind of ability, it is an additional cost on the declaration of the attacker.
No other card is named in this ruling.