Terms · 45 metrics
Glossary
For how the numbers are calculated, see the methodology in detail (Japanese).
Mahjong terms
- Riichi
- A declaration made with a closed hand in tenpai.
- Dama
- Keeping a closed tenpai hand without declaring riichi.
- Tenpai
- A hand one tile away from winning.
- Shanten
- The number of steps a hand is away from tenpai; a tenpai hand is 0-shanten.
- Deal-in
- A discard that allows another player to win by ron.
- Exhaustive draw
- A hand ending without a winner because no playable tiles remain in the wall.
- Tsumo
- A win on a self-drawn tile; the word also refers to drawing a tile.
- Ron
- A win on another player's discard.
- Ukeire
- The tiles, or number of remaining tiles, that improve a hand.
- Tile efficiency
- Choosing discards to keep a hand moving toward tenpai efficiently.
Concepts
- Estimate (skill estimate)
- The actual record shrunk toward the league average. With few games luck weighs heavily, so the estimate stays close to the average; the more games, the closer it comes to the actual record.
- Weight of the record
- How much of the player's own record goes into the skill estimate (
n ÷ (n + k)); the league average fills the rest. It approaches 100% as games add up. It is not the probability that the player is strong. - Count to half stability
- The number of observations at which the weight of the record reaches 50%. A lower count means the metric reveals a player's individual tendencies sooner.
- 90% interval
- The uncertainty of the estimate: built so that, across all players, the true value of at least 90% of them lies inside it.
- Percentile
- Position among the players with enough games in the same season (100 is best). Style metrics have no good or bad side, so there 100 is the highest value.
- Style tags
- Given when the career estimate is in the league's top (or bottom) 25% and the weight of the record for that metric is at least 50%.
- Hand balance breakdown
- The points won or lost per hand, split into wins (riichi, calls, dama), deal-ins (to riichi, open hands, dama), others' tsumo and the rest. They add up to the average balance per hand.
- Tile efficiency match rate
- The share of early and middle discards, with no riichi out, that keep the most tiles left that advance the hand (maximum ukeire). Speed-first hand building scores higher. It shows no link to results, so it is treated as a difference of style, not of quality. More (Japanese)
- Tenpai turn (luck-adjusted), immediate riichi rate
- In hands that reach tenpai closed by turn 12: the tenpai turn with starting hand and draw luck set to average, and the share of riichi declared as soon as tenpai. The immediate riichi rate is compared as the difference from each season's league average. More (Japanese)
- Dama rate
- The share of wins made without riichi or calls. Aligned with the Paifuya and Tenhou definition on 9/28.
- Luck metrics
- Differences from the league average; plus means luckier than average. Luck is not skill, so no estimate is made.
All metrics
| Group | Metric | Unit | League average | Count to half stability |
|---|---|---|---|---|
| Results | Average placement | games | 2.50 | 146 games (62–no upper bound) |
| Results | Points per game | games | 0.0 | 136 games (56–no upper bound) |
| Results | Points per game, luck removed | games | 0.0 | 98 games (41–no upper bound) |
| Results | 1st-place rate | games | 25.1% | 128 games (62–no upper bound) |
| Results | 4th-place rate | games | 24.9% | 121 games (51–no upper bound) |
| Style | Win rate | hands | 20.0% | 793 hands (495–1,992) |
| Style | Deal-in rate | hands | 10.9% | 938 hands (623–1,819) |
| Style | Riichi rate | hands | 22.7% | 738 hands (450–2,228) |
| Style | Call rate | hands | 23.0% | 66 hands (47–103) |
| Style | First riichi rate | riichi | 76.0% | 452 riichi (180–no upper bound) |
| Style | Average riichi turn | riichi | 9.34 | 170 riichi (113–409) |
| Style | Average win value | wins | 6,590 | 248 wins (138–1,398) |
| Style | Average deal-in value | deal-ins | 5,626 | 294 deal-ins (105–no upper bound) |
| Style | Win efficiency | hands | 1,474 | 8,611 hands (1,687–no upper bound) |
| Style | Deal-in loss | hands | 639 | 2,297 hands (975–no upper bound) |
| Style | Net efficiency | hands | 835 | 1,987 hands (913–no upper bound) |
| Style | Push rate vs riichi (1-shanten) | hands facing riichi | 40.8% | 182 hands facing riichi (106–810) |
| Style | Push rate vs riichi (2+ shanten) | hands facing riichi | 25.6% | 91 hands facing riichi (63–194) |
| Style | Tenpai rate after the first call | first calls | 25.6% | 62 first calls (41–138) |
| Style | Average win turn | wins | 12.38 | 4,109 wins (354–no upper bound) |
| Style | Tenpai rate at exhaustive draws | exhaustive draws | 40.0% | 179 exhaustive draws (116–508) |
| Style | Staying in vs riichi | hands facing an opponent’s riichi | 14.1% | 2,028 hands facing an opponent’s riichi (530–no upper bound) |
| Style | Tile efficiency match rate | discards | 72.9% | 337 discards (285–429) |
| Style | Average ukeire loss (tiles) | discards | 1.06 | 595 discards (501–742) |
| Style | Breaking shape for value | discards | 2.0% | 955 discards (755–1,299) |
| Style | Tenpai turn (luck-adjusted) | tenpai hands | 8.17 | 1,646 tenpai hands (288–no upper bound) |
| Style | Immediate riichi rate | tenpai hands | 71.6% | 111 tenpai hands (73–204) |
| Style | Dama rate | wins | 13.3% | 62 wins (50–89) |
| Style | Riichi income | riichi | 2,623 | 371 riichi (187–no upper bound) |
| Style | Riichi win rate | riichi | 46.0% | 175 riichi (111–380) |
| Style | Riichi deal-in rate A | riichi | 14.3% | 2,594 riichi (347–no upper bound) |
| Style | Riichi deal-in rate B | riichi | 11.0% | 912 riichi (293–no upper bound) |
| Style | Riichi good-wait rate | riichi | 49.7% | 299 riichi (168–1,001) |
| Style | Riichi exhaustive draw rate | riichi | 19.3% | 242 riichi (152–700) |
| Style | Call income | calls | 487 | 595 calls (228–no upper bound) |
| Style | Win rate after calling | calls | 29.8% | 256 calls (139–836) |
| Style | Deal-in rate after calling | calls | 11.5% | 256 calls (153–647) |
| Luck | Starting hand (shanten) | hands | 0 (baseline) | 6,920 hands (1,468–no upper bound) |
| Luck | Dora and red fives dealt | hands | 0 (baseline) | (almost all luck) |
| Luck | Draw luck | tile draws | 0 (baseline) | (almost all luck) |
| Luck | Ura-dora luck | riichi wins | 0 (baseline) | 918 riichi wins (188–no upper bound) |
| Luck | Ippatsu rate | riichi wins | 0 (baseline) | (almost all luck) |
| Luck | Avoiding a chase riichi (/first riichi) | first riichi | 0 (baseline) | (almost all luck) |
| Luck | Mangan+ tsumo against dealer rate | tsumo against | 0 (baseline) | (almost all luck) |
| Luck | Points from luck (/game) | games | 0 (baseline) | 2,424 games (133–no upper bound) |