Hanafuda.Online is a website for online multiplayer Koi-Koi published in 2026, developed by WsdŁia (Patrik Beke) from Slovakia with design by Ameshiko Design (Scheich Réka) from Hungary.
The website does not require registration. Users simply create a room and send an invite link to their friend.
¶ Gameplay and rules
Hanafuda.Online uses a ruleset that’s quite similar to the 2012 web game Shiragiku Hanafuda, with an uncommon combination of yaku values. It also includes a Cards of the Month yaku, and multiple ways to make Viewing yaku invalid. As of March 2026, there are no options for rules customization.
More detailed Koi-Koi rules:
- The values of Bright yaku are 15, 10, 8, and 6 points (for 5, 4, Rainy 4, and 3 Brights respectively).
- Boar-Deer-Butterflies is 5 points, plus 1 point for each additional Animal card. It does not stack with the generic Animals yaku.
- The Poetry Ribbons and Blue Ribbons yaku are 6 points, plus 1 point for each additional Ribbon card. When combined, they are 12 points plus 1 point for each additional Ribbon card. All the various Ribbons yaku are mutually exclusive.
- Blossom Viewing and Moon Viewing are 5 points each, and they require at least one other yaku before being able to end the round.
- If there are any Willow cards on the central field, Blossom Viewing is negated. If there are any Paulownia cards on the field, Moon Viewing is negated. Captured cards have no influence on Viewing yaku.
- The special Sake Cup rule is used: the Sake Cup card can count as an Animal as well as a Chaff card.
- No score multipliers of any kind are used.
- No Dealer’s Privilege rule is used.
- The winner becomes the dealer in the next round.