Norika Yamazaki, the Poet — ruling 1

A creature attacks alone if it's the only creature declared as an attacker during the declare attackers step. For example, Norika Yamazaki's triggered ability won't trigger if you attack with multiple creatures and all but one of them are removed from combat.

Norika Yamazaki, the Poet — ruling 2

You must still follow all normal timing rules and pay all costs for the enchantment card you cast this way.

Norika Yamazaki, the Poet : règles, fonctionnement et interactions (MTG)

Norika Yamazaki, the Poet 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

Vigilance Whenever a Samurai or Warrior you control attacks alone, you may cast target enchantment card from your graveyard this turn.

How it works : Norika Yamazaki, the Poet

Original English text — Wizards of the Coast / Scryfall

#1February 18, 2022· Wizards of the Coast
A creature attacks alone if it's the only creature declared as an attacker during the declare attackers step. For example, Norika Yamazaki's triggered ability won't trigger if you attack with multiple creatures and all but one of them are removed from combat.
No other card is named in this ruling.
#2February 18, 2022· Wizards of the Coast
You must still follow all normal timing rules and pay all costs for the enchantment card you cast this way.
No other card is named in this ruling.