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About Houwow Point (HP)

Detailed explanation of the Houwow Point (HP) rating system calculation and mechanics that indicate player skill.

Houwow Point (HP) is a rating metric that represents a player's skill level in Hanafuda. It is automatically calculated and updated based on the match results of sessions played using official rules (Koi-Koi, Hanawase, Inobota-Chushin, Hachihachi).

Initial Rating

All players start with 1500 HP. As you play more matches, your rating will naturally adjust towards your actual skill level.

How It Works

The HP system is based on the traditional "Elo rating" used in Chess, but has been expanded into a custom system that supports multiplayer structures and incorporates actual score differences.

The rating change is calculated by combining the following factors:

Rank ShareEvaluated by your placement in the session. Distributed evenly, so 1st place gets 1.0 and last place gets 0.0.
Score ShareThe proportion of scores acquired. This evaluates not just whether you won or lost, but the margin of victory/defeat.
Opponent StrengthCalculates an 'expected win rate' based on the HP difference between you and your opponents. Winning against higher-rated players grants more HP, while losing to lower-rated players costs more.
Play Count (K-factor)The base maximum fluctuation is set to 50 points. This maximum possible fluctuation remains constant no matter how many games you've played.

Performance Weighting

Your final performance evaluation is determined considering both Rank (50%) and Score (50%). Thus, even if you don't take first place, minimizing score losses and holding onto your points can minimize your HP drop.

Requirements and Notes

HP Match Conditions

The following conditions must be met for a session to affect HP:

  1. Uses an Official Rule Sessions using custom rules will not affect HP.
  2. Is a Rated Session HP will not change if the host turns off the "Rated Session" toggle during creation.
  3. Sufficient Rounds Played You must play at least 20% (3 rounds) of a full 12-round set for any HP changes to occur. Additionally, if you end a session before finishing all 12 rounds, the rating change amount is scaled down proportionally to the completion rate.

Score Evaluation Differences

Since rules have varying scoring nature, the method to calculate the Score Share adjusts accordingly:

  • Koi-Koi (Cumulative Score) Since scores are strictly 0 and above, your score share is calculated as the ratio of your score versus the total sum of all players' scores.
  • Hanawase, Inobota-Chushin, Hachihachi (Zero-sum Score) Since players steal chips from each other, your score share is calculated based on how many chips you've gained (or lost) normalized against the sum of the absolute values of all scores.

Minimum Rating

Your HP rating will never drop below 1.