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Original article date: September 16, 2019

Last update: May 29, 2020 (English Translation) - Original Dutch here.

Est. reading time: ± 6 minutes

This is a work in progress article, it will be updated with additional information as more and foremost more formal information becomes available to us.


Two of our club founders of our Mahjongclub "Haagse Kringen" (The Hague Circles / Dots), Paul and Peter, started to research on the Duplicate Mahjong concept seriously. At the time of writing this article, there's no formal document that describes the Duplicate Mahjong Format, where the concept has been described in all necessary details.

They hoped to have tested the concept at the end of this summer, on a small scale, within the circles of our own Mahjongclub, but unfortunately at this point (May 2020), this is not possible due to the Corona prevention measures.

This article/page is set-up to share with a larger community what our understanding of the concept is.

During this summer we expect that this concept will be available for online play at the online MCR platform


Mahjong with all of its well-known and less-known variants of rule-sets like Mahjong Competition Rules (MCR, Chinese Official), Riichi, Hong Kong, NTS (Dutch Tournament Rules), etc., all encompass a considerable luck-factor.

The mahjong tiles are, in the rulesets familiar to us all, drawn from the jointly build wall. None of the contestants has any influence on the tiles they will end up playing with, and the results can simply not be compared with each other, as every game differs from the others that will follow.

De factor luck is undeniably present in all traditional forms of Mahjong, but it is a mistake to think that the outcome of the game solely depends only on luck.


The ambitious mahjong player can try to influence his game by (1) having a thorough understanding of all the scoring elements of a game variant, (2) knowing exactly which tiles are needed to make a certain valid mahjong formation (3) try to maximize the possible chances to different alternative mahjong-formations as long as possible and (4) attempt to strategically aim for multi wait end-games. Knowledge of known statistical facts, on the most frequently played scoring elements and the associated principles of probability calculation.

All this in the context of the dynamics that our beloved game with four competing opponents brings, every single game. This also means applying tactical skills such as (6) defensive gameplay and sometimes (7) misleading moves.

There are also mental factors, such as (8) applying the skills under the pressure of the speed of the game, as well as (9) being able to deal with loss and (9) having the resilience and perseverance to focus hard every single game, relentlessly trying to get the most out of the tiles presented in each game.



Many recreational players play the game without much regard to defensive tactics, everyone knows the novice player who seems to prefer the beautiful hand or even the beautiful dragon stone as a "gem" as long as possible, because ... "you never know what luck will bring you".

By studying and developing the above skills, the player who wants to seriously improve his or her game might be able to reduce the influence of the luck factor. Therefore, there are also less fortunate players and very good players.

However, the luck factor of being able to complete your "unlucky" 13 tile hand into the "a lucky" 14 tile mahjong formation is always present to some degree.


In some of the rule-sets, only the lucky player with a valid mahjong formation wins, and in some variants, every player receives a score for any scoring element they'd manage to compose, regardless of who the winner was. In some variants, only the winner scores points, and in some variants, all points scored by each player are settled with every single player. In some variations, a player with an extremely lucky hand may score an exorbitant number of points that immediately determine the outcome of the entire evening or playing session.


To reduce the luck factor, you could of course remove certain elements of "luck" from the game. The most obvious element is the entire set of 8 flower and season tiles, for a good reason most often called tiles of luck. In addition, you could limit so-called limit games that can lead to extreme point totals. In the discussion about which factors you should or should not eliminate, sooner or later the argument will come up "yes but if you get that out of the game, you will lose some of the charms of the game". This perhaps true, but perhaps there's also something that you will get in return!


An additional possibility is to establish a game format that will enable the possibility to compare game results between two or more individual players (or even competing teams) who have played with exactly the same starting position and under exactly the same circumstances as their opponents at another table. Surely it will turn out that based on the level of skills and their application thereof, the different players make different choices and thus will achieve different results.

An MCR example:

At an imaginary table (A) the player at West manages a 9 points  mahjong-formation (All Types, Mixed Double Chows, Middle Wait and a Pung of Winds 6+1+1+1)

At a different imaginary table (B) another player also playing at West manages to score a 14 point hand (Mixed Straight, Four Chows, and Last Tile  8+2+4)


An additional important factor is that the context of play has been made completely comparable by ensuring that the opponents in the seats East, South and North respectively have exactly the same starting tiles in their hands as the players on the other gaming table in the same position.

Each player also has a personal wall that is exactly the same for both seats on both tables.

The lucky tiles have been removed from the game on both tables.


The starting situations are the same for all each of the players in the respective wind directions, the choices each player makes are different, the level of different playing skills plays a larger role, the results are most often different.

The competitive format described above - using a somewhat simplified example - is the so-called Duplicate Format, originally conceived for the "Bridge" card game as a competition format, which has established Bridge as a Competitive Mind sport for many decades.

Applying the Duplicate Format to Mahjong and to MCR Mahjong, in particular, results in a competition format for the Mahjong Competition Rules (aka Chinese Official) where the luck factor is significantly reduced. In addition, the principles are applicable in a competitive match for both individual players and teams of players.

As far as we know, Duplicate Mahjong currently has no formal status within the NMB (Dutch Mahjong Association) and, as far as we know, not within the EMA (European Mahjong Association) as well as the umbrella WMO (World Mahjong Organization).

Several tournaments have been organized. We are aware that tournaments have been played especially in Russia. There are also a number of enthusiasts who put a lot of energy into this concept.

In our search for details about this concept and the requirements for organizing an actual tournament, we have also had contact with various people in the Netherlands, Russia, and China.

Mahjong International League is an independent organization that is committed to promoting Mahjong as a mind sport, whereby the Duplicate competition form is a requirement.

UPDATE April 2020

Recently, the site, an online MCR platform (a non-commercial initiative of Alexander Egorov, Vitaly Novikov, and Denis Lugannikov)  have launched focused efforts to make this competitive game and tournament format available to their community of online players. Since their launch, a  delegation from Mahjongclub Haagse Kringen has now been able to participate in a first pilot team "tournament" and subsequent Individual "tournament" sessions as well. Hopefully this summer the concept will be developed in such a way that actual online tournaments can be organized.

Perhaps we can utilize the site to organize an online tournament this summer for our own club members and later for Dutch Clubs or Teams, we are anxiously awaiting the new developments and opportunities.

UPDATE May 2020

In the meantime, there have been multiple pilots for Teams and Individual Duplicate tournaments.  The concept is being formalized into software rules that enable the online player to enjoy this new interesting competitive format.

Below a short video recorded by Vitaly Novikov where he introduces Duplicate Mahjong on the online MCR platform.

The pressing question for many is, what exactly is Duplicate Mahjong?

As mentioned, Duplicate Mahjong is a competition format in itself. The competition format dictates a number of things:

  • That it should be possible to compare opponents' mutual game results ...

  • where it is essential that only the game results are compared where the opponents had the exact same context in terms of the initial situation of a given game.

  • A rotation schedule ensures that all participating contestants (as a team or as an individual) each had the same starting point.


Briefly summarized:

The opponents play under the same conditions, the game results are compared.

The score of a given hand is calculated from the average results for the given game from all opponents.

There are all kinds of details regarding this competitive match format, it is however beyond the scope of this introductory article to dive into all the details, even though these underlying details are essential to organize a match / tournament with such a Duplicate Format.

At a high level it is important that:​​

  • The tiles are prepared into sorted table sets.

  • The table sets are restored to the starting position after each hand played.

  • The table sets are then moved to other tables in another round according to a set scheme.

  • The players switch from table to table according to an exact rotation schedule.

  • That a player's particular seat has been determined by an exact schedule.

  • The participating individual contestants or team players may not speak among themselves, possibly with the implementation of dividing screens or separate playing areas, for example.

In any case, it is possible to properly implement such a schedule with 4 teams of four persons with a session of four rounds of 16 prepared "game boards", a tournament could then include, for example, 4 sessions. In theory, it should also be possible with individual players or with teams of 2 players or eight players, this has an impact on the number of games to be played. A tournament can also be organized with more than 4 teams. It is also exactly the particular details that we are also very interested to learn about in order to assess what is necessary to organize a live tournament.

In addition, the initiators of the concept have come up with the idea that taking into account the wish to put Mahjong on the map as a Mindsport with this format, also remove a number of elements from the game that are related to luck.


In that sense, MCR is not the only variant on which you could possibly apply the duplicate format. We understand that the SBR (Sichuan Bloody Rules) variant is also suitable for this format. There may be more Mahjong variants that lend themselves to this particular format too. In this article, we stick to MCR only for the time being because the members at our club only play MCR.

Daarnaast hebben de bedenkers van het concept bedacht bedacht dat rekening houdend met de wens om Mahjong als denksport op de kaart te zetten met dit formaat ook een aantal elementen uit het spel die met geluk hebben te maken te verwijderen uit het spel.


In die zin is MCR ook niet de enige variant waar je het duplicate formaat op zou kunnen toepassen, naar wij hebben begrepen leent ook de SBR (Sichuan Bloody Rules) variant zich voor dit formaat. Wellicht zijn er meer Mahjong varianten die zich hiervoor lenen. Wij houden het hier voorlopig bij MCR omdat op onze club alleen MCR wordt gespeeld.

Below a brief video presentation produced by the MIL (Mahjong International League.

So, what is the impact on the MCR ruleset?

  • The lucky tiles (flower and seasonal stones) are exempt from the game

  • So there are 136 stones in the game

  • The rolling of dices to determine wall building end determining seating is exempt from the game.

  • Each player has a personal wall.

Impact on scoring elements (fan)

  1. The scoring element for Self-drawn, +1 point, still applies, however, the scoring bonus as we are familiar with has been adapted to facilitatie less impact on this "lucky draw"! Instead of the traditional scoring settlement, the winner gets the hand value + 24 points and the losers each (hand value +24) / 3, a possible fractioned result is rounded up.

  2. Multiple winners are possible! whereby there will also be a mutual settlement of points.

  3. No Kong declaration possible when the personal wall is finished! replacement bricks can only be pulled from the personal wall.

  4. Mahjong with the Last Tile Drawn, if the player's personal wall on the right side of the one who declares Mahjong has run out. So that player cannot make another turn by taking a brick from his personal wall.

  5. The Last Tile Claimed scoring element is possible for a player whose opponent on the right side no longer has a personal wall.

Note: We will create a page at a later stage where all details have been worked out, including the adjusted rules and the score calculation.

Impact on the MCR gameplay

  • Each player plays with a personal wall in every game

  • The personal wall of 21 tiles consists of a bottom layer of 11 tiles and with a top layer of 10 tiles.

  • Each player has 13 open tiles.

  • Each player takes tiles from the personal wall only.

  • For a replacement tile on a Kong declaration, the next tile is taken from the personal wall - not from the (left) end of the wall!

  • A draw occurs when a player has depleted his/her wall and the opponent to the left has only one tile left in his next turn (Last Discard) who still scores the Last Tile Claimed points.

mahjongsoft duplicate mahjong.png

image used with permission - courtesy

Impact on score settlement

IMP introduction - The Duplicate format utilizes a concept known as IMP, an acronym for International Match Points. It is a method that encompasses an internationally adopted standard to express a core where the opponents played under (exact) duplicate circumstances in terms of prepared "game boards", in the Bridge Card-game this is called a "board".  Depending on the Gamepoint scores relative to the opponents, the players will either be awarded a positive or negative  IMP score.

Duplicate Teams

  • The total number of Game points for a given hand played is calculated for the entire team, compared to the opponents Game points and converted into IMP.

  • The total Team IMP is the sum of the IMP for 16 hands,

  • The result is determined on the basis of the IMP total per team.

Duplicate Individual

  • The average number of points for a hand played by each participant is calculated.

  • Then, for each player, the difference of their own score is compared to the average score and converted to an individual IMP for the hand played.

  • The total of the IMPs for the played hands.

  • The result is determined on the basis of the IMP total per individual player.


Online Mahjong Etiquette

  • If you have an unreliable network connection, consider not participate, as it may considerably impact everyone's experience of the entire online sesion. 

  • You start with 16 players, you also end with 16 players. You don't just get out, you finish the entire playing session.

  • If you have a network problem, close the game tab and choose JOIN TABLE again. The game continues with 9 seconds elapsing before your turn as long as you are not able to reconnect properly.

  • Online Mahjong gameplay is faster than a live game, however with a duplicate match you expect the following:

    • Each playing hand is started synchronously. After your table completed the hand you may have to wait until all tables have finished their hand as well. yes of course there sometimes is a fast table and of course also draws occasionally  occur! Be patient.

    • On average, a 20 hands (5 rounds) game lasts about 100 minutes (the fastest -at the time of writing- took about 80 minutes, the longest over 120 minutes)

  • There are individual tournament sessions and team tournament sessions (4 teams of 4 people)

  • You are playing a Duplicate Mahjong match session with 16 players.

  • The system generates a random schedule for all sixteen players.

  • Each round, you always play against three other opponents (out of 15 opponents), against whom you have not played in the previous rounds.

  • The move timer is set at 9 seconds.

  • At the end of the move timer you will hear a beep.

  • When the timer has expired and you have not discarded a tile yourself, the system chooses a random stone from your hand as a forced discard. The system keeps a counter for any missed turn.

  • The system offers Hu! also if the Hu! may not be valid (in terms of sufficient points)! it is up to you whether to accept the proposal or not. A false Hu! is therefore very possible!

  • A false mahjong event is displayed to all players, close the window with an X, the penalty points are automatically imposed during the score settlement.

  • The system also offers the option of a tile to be claimed, it is up to you to decide whether to accept or fit one of the possible proposed sets.

  • If you have the fourth tile of the Kong in your hand, you will again have the opportunity to declare a Kong at every turn where a tile takes off the wall.

  • After ten complete hands, there is a 5-minute break.

  • The system automatically calculates the mahjong points (GP) and the derived IMP per player/team. These can be viewed during the match and after the match via the statistics page.

Are you interested in playing this format and would you like to be kept in the loop on any developments, then fill out this form,  you will be included on a distribution list, where we will keep you appraised on news and developments and possibilities to join tournaments.

If you have questions about Duplicate Mahjong of information to share that we have not shared on this page, please feel free to contact us using the same form.


The Duplicate Format is now being fully deployed and tested on the online platform, you can just join the open sessions to get acquainted with this new game format. Don't be afraid to do something wrong! You just play mahjong (with the described adjustments) and because it is an online environment you do not have to worry about the technical details.


Mahjong International League website (en)

Vitaly Novikov (Rusland)

Li Wenlong (China)

MCR Duplicate (MIL site) (en)

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