Koa'ki Ring is a Normal Spell Card.
Spell Cards are usually activated from the hand on your turn unless their type gives another timing window.
On the current TCG and OCG Forbidden & Limited lists tracked here, Koa'ki Ring is Unlimited.
YGOPRODeck lists Koa'ki Ring for these formats: Common Charity, TCG, OCG, Master Duel.
Koa'ki Ring belongs to the Koa'ki Meiru archetype—use that tag when searching for engine pieces and tech options.
A listed print of Koa'ki Ring appears in Starstrike Blast (STBL-EN056) at Common rarity.
Among markets shown on this page, the lowest listed snapshot for Koa'ki Ring is about $0.08 on TCGPlayer (prices change frequently).
