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Xeno Koi Wiki

Xeno Koi is a digital Koi-Koi (Hanafuda) game with five rule variations, a CPU opponent campaign, and a biomechanical CRT presentation. This wiki explains how to play, what each ruleset changes, and how every point is scored.

The five Brights — the most valuable cards in the deck:

01-B Crane 03-B Curtain 08-B Moon 11-B Rainman 12-B Phoenix

Left to right: Crane (January), Curtain (March), Moon (August), Rain Man (November), Phoenix (December). Combos of these are on the Yaku & Scoring page.

Start here

  • Never played? Go through Play it in three turns -- one round played out, one idea per line, real cards at every step.
  • New to Koi-Koi? Read How to Play first. It covers the deal, a turn, calling Koi-Koi or Shobu, and how a round ends.
  • Choosing a rule set? See Rulesets. The Options menu lets you pick one of five.
  • Want the exact scoring? See Yaku & Scoring and Multipliers.
  • Working through the campaign? See Modes & Settings for clearance coins and sector requirements.
  • Custom music or action-audio effects? See custom music and Options page 2 action audio, including the live ON/OFF audition.
  • Playing KK-ADD-10? Its speed minigame explains the 1000 ms bar, serie bonus, and match-end minipoint conversion.
  • Looking up a card or opponent? See Cards and Opponents.

Rule sets at a glance

Rule set One-line summary
Nintendo The classic balanced baseline. One Koi-Koi call per player per round.
FudaWiki Nintendo with bigger Goko and Sanko, and unlimited Koi-Koi calls.
KK-ADD-10 The maintainer's house rule, and a good place for beginners to start. Fixed sets stack with counted cards, the Sake Cup counts as a plain, and the speed minigame converts minipoints at match end.
Tournament Nintendo scoring with both Viewings removed. The Sake Cup is only an animal.
Yakuza Tournament scoring plus Dealer's Privilege: a draw pays the dealer 6 points.

Source of truth

This wiki is the current reference

The wiki describes the game as it is now. Older documents are history, not rules:

  • This wiki and the code in src/ are the source of truth.
  • HANDOFF_KoiKoi_Giger_v2.pdf is legacy. It was the original build spec. Its rules were later changed, and it has not been updated since. Use it only for history. Errata & Known Issues lists every place it differs from the game.
  • STATUS.md is the dated development handoff, not a rulebook or deployment record. It reports the local source status and checks recorded on its stated date.