Free tools & stats数字
Riichi by the numbers
Every tool on this site that runs on real game data, on one page. Pick the decision you're stuck on and get the number behind it.
Your wait, their riichi
How often your wait wins, when to push against a riichi, and how dangerous the dora is.
Is the caller tenpai?
Tenpai odds for an open hand by calls, turn, hand type and tell.
Where you finish
Your odds in the last hand, and where your placement rates take your rank.
Where the numbers come from
Tenhou Houou logs 2016–2020, analysis by chienshyong (fork of Euophrys/houou-analysis); wait win rates from Path of Houou; push/fold chart by epsilon69399
Each tool page names the table it reads and what the numbers count. They're statistical guidance for Houou-level 4-player hanchan. Your table, the scores and your reads can make a different play right.
The rank calculators combine each server's rank rules with the placement rates you enter.
Coming articles
Each one explains the numbers behind one of the tools above.
- What folding in riichi mahjong costs: 1,100 to 1,900 points
- Riichi wait win rates by turn: suji traps, honors, and dama
- How dangerous is the dora? Riichi and open-hand deal-in odds
- Is the open hand tenpai? Tenpai odds by calls and turn
- All Last math: your real odds of finishing 4th by score gap
Want a pro to check your real hands?
These numbers describe the average hand at Houou level. Your games have their own leaks. Send me a log and I'll show you where the numbers say you're losing points.
Twenty hands.
Pick your discard.
A free nanikiru deck from a Japanese professional mahjong player (JPMA) in Osaka. It starts with loose tiles and ends with a riichi on the table. Every answer shows the tile count behind it.
- Twenty problems, in order. Fundamentals first, then shapes, value, riichi waits and one defense spot.
- Answers on their own page. Decide first, then check. No peeking by accident.
- Printable PDF. Do one a day, or all twenty on the train.
I'll email you a link to confirm, then the deck. After that, a few short emails on how to use it, then new problems and guides about once a week. One click unsubscribes. Privacy policy