AI Statistics
Our Fair Play page shows, with source code, exactly what the CPU opponents can and cannot see. They never see your hand, the wall, or any hidden tile. This page is the companion in numbers.
How we measured
We ran 10,000 hanchan (427,820 player-hands) of the Normal AI playing itself on the default rules (four players, three red fives), with all four seats on the Balanced playstyle, the default, using version 1.15.0, and computed per-hand statistics from the complete game records. For the human side we cite only independently published figures, each linked. No number in the human column is ours.
The numbers
| statistic | Agari Normal AI | published human figure | source |
|---|---|---|---|
| Riichi declaration turn, average | 8.86 | 8.81, computed from the per-turn declaration counts printed at the source (the page itself states the peak is turn 8, 「立直は8巡目がピーク」) | kobalab (turn analysis) |
| Riichi declaration turn, 10th / 50th / 90th percentile | 5 / 9 / 13 | 5 / 9 / 13, computed from the same printed per-turn counts | kobalab (turn analysis) |
| Winning turn, average | 10.80 | 10.96, computed from the per-turn win counts printed at the source (the page states the peak is turn 10, 「和了は10巡目がピーク」) | kobalab (turn analysis) |
| Win rate, per player-hand | 20.8% | 21.1%, printed as 和了率 .211 | kobalab (2023 logs) |
| Deal-in rate, per player-hand | 12.3% | 12.4%, printed as 放銃率 .124 | kobalab (2023 logs) |
| Ron / tsumo split of wins | 60.1% / 39.9% | 59.5% / 40.5%. "59.5% of wins are ron" is quoted verbatim. The tsumo share is its complement, and the two always sum to 100% | independent game analysis |
| Ippatsu, share of riichi wins | 18.2% | 19.2%, computed as 120,275 ippatsu wins over 627,241 riichi wins, both counts printed at the source | kobalab (2023 logs) |
| Riichi rate, per player-hand | 22.4% | 18.4% in 2023, printed as 立直率 .184. 17.0% in 2016, printed as 立直率 .170 | kobalab 2023, kobalab 2016 |
| Call rate, per player-hand | 28.4% | 32.6% in 2023, printed as 副露率 .326. 34.4% in 2016, printed as 副露率 .344 | kobalab 2023, kobalab 2016 |
Where the AI differs
The Normal AI declares riichi on slightly more of its hands than the published averages, and it calls slightly less. It leans toward playing its hand closed. Its timing, win rate, and deal-in rate land on the human numbers.
Measurement notes
These figures were measured on version 1.15.0. The published sources describe four-player hanchan with red fives at the top level of online play. Our measurement uses the same format and rules. Self-play tables seat four identical opponents. The published baselines average many different elite players. Where sources disagree across eras we list both figures. Riichi rates have risen and call rates fallen in top-level play over the last decade.
Figures quoted as printed include the exact string the page uses. The kobalab pages print rates as decimal fractions, where 和了率 .211 means a 21.1% win rate. Figures marked as computed are arithmetic over counts printed at the linked source, with the inputs named.