What is tenpai in mahjong?
Tenpai means your hand is one tile away from a winning hand. Reading tenpai is a core skill in competitive mahjong. Mahjong Lab’s tenpai training helps you get faster and more accurate.
Read Hands Faster. Discard Smarter.
Focused drills for tenpai, discards, and shanten. Every answer is computed tile by tile with an exact algorithm, so you see the best discard the moment you answer. Free, no sign-up needed.
Which tile would you discard?
11 tilesTap a tile in the hand to discard it and compare acceptance.
7 training modes · 4 languages · No sign-up needed
What Mahjong Lab is for
Mahjong Lab is an online mahjong training platform focused on tile efficiency and in-game decisions. Core skills—tenpai reading, discard choices, shanten calculation, and yaku recognition—are split into focused drills you can repeat until they feel automatic.
The site includes tenpai, discard, shanten, one-shanten acceptance and discards, yaku, and scoring modes, plus a hand analyzer for shanten, waits, and discard comparisons. Every drill gives instant feedback with an exact acceptance breakdown, so you can improve systematically from beginner to advanced play.
You can practice without signing in. Sign in to save scores, join timed leaderboards, and take the daily challenge. Illustrated guides explain each concept first and link straight to the matching drill when you are ready to train.
7 focused drills, in this order
Start with counting shanten, then tenpai, acceptance, and discards, then yaku and scoring. Every mode has practice and timed play, or jump straight to your weak spot.
- 1Shanten CountCalculate the number of steps away from a complete hand
- 2TenpaiImprove tenpai recognition speed and accuracy
- 3One-awayPractice identifying one-away hand patterns
- 4Discard DecisionTrain tile discarding decisions to maximize efficiency
- 5One-away DiscardTrain optimal discarding in one-away situations
- 6Yaku RecognitionPractice identifying hand-inherent yaku
- 7Score CalculationPractice fu, han, and payment from yaku names and seat context
Daily Challenge
One set for everyone, every day: 5 tenpai and 5 discard questions, ranked by correct answers and time.
- 10 questions a day
- Resets each UTC day
- Sign in to join the daily board
Understand it first, then drill it
Illustrated guides with real tile examples for shanten, acceptance, discards, and yaku. Each one links to the matching drill.
- User GuideGuide for the mahjong tile efficiency training tool. Learn to use Daily Challenge, tenpai, discard, shanten, one-shanten, yaku recognition, and hand analysis with keyboard shortcuts.
- Tile EfficiencyTile efficiency ranks a discard by lower shanten, then more ukeire copies, then more kinds. Forty hands cover live copies, ties, waits, score, defense, furiten, and each ruleset.
- ShantenCount mahjong shanten as steps to tenpai. 0 is tenpai, 1 is one-shanten, and a finished win is −1. The minimum covers 4 melds + 1 pair, seven pairs, and kokushi, then 14-tile cuts, improvements, 立直, 国标, and 川麻 定缺.
- UkeireCount ukeire as kinds and hand-only copies, then read 立直, 国标, and 川麻 sidebars for waits, scoring draws, and the missing suit.
- DiscardChoose the discard from a closed 14 by lower shanten, then more ukeire copies, then more kinds. Ryanmen against nobetan, tanyao, a wind triplet, furiten, 国标 suit plans, and 川麻 定缺 sit beside that ladder. Practice is discard training.
- Riichi YakuNo yaku cannot win. A finished shape still needs one yaku. The han list runs from 1 han to yakuman, including closed vs open hands and kuisagari.
Frequently Asked Questions
What is tile discard efficiency (何切)?
It’s choosing which tile to discard so your hand keeps the most useful draws and stays efficient. Our discard training uses precise shanten and acceptance so you can make better decisions.
What is shanten number?
Shanten is how many effective swaps your hand needs to reach tenpai. 0 shanten = tenpai, 1 shanten = one away. Getting shanten right is how you evaluate hand progress.
How can I improve my mahjong tile efficiency?
Systematic practice with instant feedback works best. Mahjong Lab offers focused tenpai, discard, shanten, and yaku drills, and every answer shows an exact acceptance comparison so you can target your weak spots.
What training modes does Mahjong Lab offer?
7 focused drills: shanten, tenpai, one-shanten acceptance, discards, one-shanten discards, yaku recognition, and scoring. There is also a daily challenge and the Hand Analysis tool. Every mode supports practice and timed play.
Make the next discard the right one
Start free; pick a mode and go. Every answer is checked instantly with the best discard and its acceptance.