September’s Hanafuda suit is chrysanthemum. In the Koi-Koi card set, the ninth month features the sake cup, a blue ribbon, and two chaff cards.

Kokugakuin University’s Encyclopedia of Shinto identifies Choyo, also called Kiku no Sekku, as the Chrysanthemum Festival held on September 9. Its article connects the date to chrysanthemum-petal wine, longevity wishes, and older seasonal festival practice.

The Sake Cup

In Koi-Koi’s current ruleset, the sake cup counts as an animal/object card. It also enables two cup yaku when those house rules are active: moon with cup, and curtain with cup.

Other rulesets may also count the sake cup as chaff. The rules described here are the app’s defaults.

The Blue Ribbon

Card 33 is a blue ribbon. In Koi-Koi, the blue ribbons in June, September, and October form the Aotan pattern.

Two Chaff Cards

Cards 34 and 35 are chaff. Collecting enough chaff cards scores Kasu.

How We Know

The deck structure comes from Nintendo Museum’s description of Hanafuda as a 48-card, 12-month deck. Card classifications and rules are sourced from the Koi-Koi rules documentation. Choyo no Sekku context comes from Kokugakuin University. Where Koi-Koi marks a rule as variable, this article marks it as variable too.

Sources

  1. Try Playing Hanafuda!, Nintendo Museum. Accessed 2026-09-01. Used for the 48-card, 12-month Hanafuda structure and Nintendo Museum workshop context.
  2. Choyo, Kokugakuin University Digital Museum, Encyclopedia of Shinto. Accessed 2026-09-01. Used for Choyo no Sekku, chrysanthemum wine, and festival history.
  3. Koi-Koi - Rules & Variants, Koi-Koi repository. Accessed 2026-09-01. Used for the current Koi-Koi ruleset and house-rule disclosure.
  4. Cultural Reference - Hanafuda & the Twelve Months, Koi-Koi repository. Accessed 2026-09-01. Internal topic map only; not treated as external factual authority.