Understanding RNG

Introduction
Mahjong Time receives occasional questions and concerns regarding  the fairness/ randomness of the gameplay on the site. While every player’s opinion and feedback is very important to Mahjong Time (we read every email and reply to nearly each one), I would like to offer the community my perspective on this issue. Admittedly, I am not a mathematician or statistician, but through the process of building the game, constantly testing and retesting the fairness and security of the site, and discussing concerns with members of the community, I have become very familiar with this issue.

How Randomness Works at Mahjong Time
Mahjong Time, just like most of other online gaming websites uses a special program called the ‘Random Number Generator’ (or RNG for short) to randomise every single game played on the site. The RNG is not a simple tool; it uses formulas called algorithms which are a series of instructions to generate the numbers that correspond to the different aspects of the game. The complexity and scope of these algorithms are beyond most of our mathematical knowledge, but through testing and analysis have proven to be accurate and dependable in generating random numbers.

The RNG works to generate the wall before each hand, and just like in real life, the tiles are then drawn from the shuffled wall in the middle of the table. This method has been been key in simulating real-life Mahjong from the very first version of the game. Mahjong Time even hosted a test a few years ago in which players joined a Mahjong Time game, the wall was generated, and players began to draw tiles from the wall as our staff sent out chat messages to make sure that the tiles did in fact come out of the wall and were not generated when drawn. This test demonstrated that the wall was in fact generated before the game.

Truly random numbers are the heart of online gaming. The entire Mahjong Time business depends on games being fair and secure, so that we may be recognised by all players as a credible and safe place to play. Mahjong Time succeeds simply by offering the best online mahjong experience for our players. I cannot imagine a reason for Mahjong Time or any other online gaming website to favor any player or group of players in any way. Favoring any group would drive away any players not in that group, and that’s simply bad for business.

While everything i’ve stated above is fact, it has still been difficult to gain the confidence of every player at Mahjong Time.

Psychology of Randomness
I believe that the concerns that players have are not rooted in the system’s programs or algorithms, but are in the psychology of pattern recognition. As humans, our brains are very good at analyzing information and developing patterns based on our observations. If we observe a common event (like having a dragon tile in your hand, for example), we recognise it as common and think nothing of it. The opposite is true for a rare event. If we observe a rare event (like starting with all four white dragons in your hand), we recognise that it seldom happens and process it accordingly. So, theoretically, rare events in Mahjong should happen rarely. However, the term “rare event” is not defined.

There are many examples of “rare events” in Mahjong, such as:
-Starting with all four dragons in your hand
-Assembling an All Kongs hand
-Winning five times in a row (assuming properly matched skill levels)
-Picking the same tile from the wall three or four times in a row
-a few self mahjongs in a row
the list can go on, and on, and on. So because there are so many examples of “rare events” any player is bound to see one eventually, making all of them, as a group, not rare at all. Even the rarest of events (lets say 1 in 10,000 chance) will statistically happen at Mahjong Time today in the tens of thousands of hands that will be played at Mahjong Time today. So it’s no surprise that many players see rare things happen constantly while playing.

Let’s take an extremely rare example of winning the lottery twice in one year. Statistically, this will never happen to you or me (I don’t buy lottery tickets :) ). But, when the very small chance of winning a certain lottery (1:5,153,632) is expanded to the scale of everyone who plays the lottery, one person ends up winning twice in one day: http://usnews.msnbc.msn.com/_news/2012/04/24/11370933-lucky-mistake-virginia-woman-wins-1-million-lottery-prize-twice-in-one-day?lite

A common question I receive on this topic is “When playing real-life Mahjong I see a self-mahjong 2-3 times in one evening, but at Mahjong Time is see it happen 5-6 times in a evening. What’s going on here? Is Mahjong Time favoring the self-mahjong?” Well, when I play Mahjong in real life, a hand can take 20-30 minutes, with setting up the wall by hand, throwing dice, talking with my friends and family at the table. One great thing about Mahjong Time is that the set up is automated, there is a move timer, etc., which means that you can play a hand twice as fast. Therefore, you can play twice as many hands in a evening, and consequently, see twice as many self-mahjongs.

Another example of player feedback we have received addresses a perceived increased rate of self-drawn wins: “The game has flaws, too many self mahjongs” I don’t know what the “ideal” rate for self-drawn wins is supposed to be. In my experience it has always varied depending on the style I’m playing and the skill level of my opponents. More skilled players tend to not throw “hot” tiles (tiles that someone can use for Mahjong) as often. I am a player of moderate skill level, and even I have felt a sixth sense for tiles to absolutely NOT throw in order to not give my opponent Mahjong. So perhaps, when players improve in skill and start playing against more advanced opponents, they see more self-drawn wins.

One thing that cannot logically cause more self-drawn wins is the RNG or Mahjong Time program in general. As I said above, the wall is generated before the game, so there is no way that the RNG can decide who gets what kind of Mahjong. This kind of logic is akin to blaming the person who shuffled the tiles in real life for the series of moves each player makes during a game that lead to Mahjong. And once again, there is no imaginable business reason we would favor any players.

You win some, you lose some...
Unfortunately, bad outcomes seem to stick out in one’s mind far more than good ones. it would be fantastic if our minds worked the other way around. Everyone loves to win, and wants to win all the time, but we are disappointed at our losses.  I found it curious that in all the years that Mahjong Time has been operational we have never received an email saying “I won 5 times in a row, your Random Number generator is broken!” However, “I lost 5 times in a row, there is a problem with the RNG” is quite common. And as I said, all feedback is read and appreciated, but I assure you, Mahjong Time is never responsible for your win or loss.

I would love to hear your opinions and perspectives on this issue. This article is meant to be an open discussion. Do you feel that Mahjong Time is fair? Are you confident in how the wall is generated? Have you seen any interesting, rare or even bizarre outcomes in a game?

Thank you for reading, please let us know if you found this interesting or if you have any opinions you want to share below.

Best regards,
Slava Novozhenya
Mahjong Time CEO

a3geffen's Hints and Pointers – seven pairs

There are quite a number of manuals on the basics of how to play a game of mahjong. The amount on strategy and tactics however is limited. Mahjong Time has asked Adrie van Geffen (a3geffen) to share his views in that territory. In the year 2011 he will publish a series of articles with hints and pointers having to do with strategy of mahjong in the different styles (except American): Hong Kong (HK); European Classic (EC); Mahjong Competition Rules (MCR); Riichi Competition Rules (RCR); Taiwanese (TW). Below part 13 – seven pairs.

One of the special hands in mahjong that has quite a good chance to be successful is seven pairs. Special hands often depend on the starting tiles and most of them better be almost complete. That is not the case with seven pairs. It could well be that after a few turns you have four pairs. Then already it is time to choose. If you want to finish with a pung hand then you’ll need five tiles. If you choose to go for seven pairs then you only need three.

Going for seven pairs is a matter of self control. Don’t pung and be determined. When you pick up a tile that makes a pung from one of the four pairs, you’ll probably discard one of the loose tiles to keep the options open. But when it comes to claiming a discard, you already have to have made up your mind and estimated you chance of success. And of course seven pairs means quite a lot of points, more than pungs or other hands that could be considered.

If your hand evolves to one with five pairs of tiles you still have choices. Four tiles needed for a pung hand, but only two for seven pairs. In my experience when I make a pung with tiles like that, the next turn I have one pung on the table and six pairs in my hand. With five pairs I almost surely will go for the seven. Unless I see that another player, dangerous in the score, is going for a chow. I may be a spoilsport and pung for defensive reasons.

In the style TW it is of course even more special for in reality you have to have eight pairs and one tile to promote one of them to a pung. Once in awhile I make a false mahjong, in all variants. Lack of concentration or bad counting. Making a fals mahjong in EC is rather difficult, but I have succeeded. Thinking that special hands are more or less the same in all styles, to my surprise seven pairs is not a combination that is permitted in EC. At least it makes the choice to go for pungs a lot easier. Besides that every pung means points gained in EC style.

Written by
Adrie van Geffen

homepage: http://homepages.ipact.nl/~geffen

a3geffen's Hints and Pointers – mind the score

There are quite a number of manuals on the basics of how to play a game of mahjong. The amount on strategy and tactics however is limited. Mahjong Time has asked Adrie van Geffen (a3geffen) to share his views in that territory. In the year 2011 he will publish a series of articles with hints and pointers having to do with strategy of mahjong in the different styles (except American): Hong Kong (HK); European Classic (EC); Mahjong Competition Rules (MCR); Riichi Competition Rules (RCR); Taiwanese (TW). Below part 12 – mind the score.

For the last year I have played almost every weekday to earn me some golden coins. With them I have played almost all tournaments on Saturday (GMT). Besides that I have played quite some live tournaments in the last years. And of course I play every week at the club ENMV in a club competition. I think that qualifies me as an experienced tournament player. Playing tournaments holds an aspect that I still haven’t mastered yet but I’m definitely working on. And it is easier playing online than in live tournaments: checking the total scores and adjusting strategy to that.

As a starting player you only have one thing on your mind and that is making mahjong and winning the game. But when you play tournaments, or even just one round of mahjong, you should take into account what your position is. In the qualification rounds of Sit & Go tournaments for golden coins you need to end as first or second, in GMT’s or playing live you want to get as many table or tour points as you can get. But all too often I see a player, at that moment 3rd or 4th, make mahjong in the last game and score not enough points to gain a rank. Absolutely useless. Digging your own grave.

Golden coins tournaments are mostly played in Riichi style. Quite often small hands are played by claiming a dragon pung or something like that and go out on a hand worth about 2000 points. When the end of a round is near and you are more than 8000 points behind it is no use to go for that kind of hand. You need bigger and you have the most chance to keep your hand concealed, have some red fives, declare Riichi and hope you’ll have the advantage of scoring Dora tiles. And give yourself the chance to get to the next round and win something.

When playing a usual round you may want to keep in mind that you are also playing for your rating. You may choose to go for a small scoring win just to control the damage done to your rating or even the ranking in a GMT. But the golden coins tournaments are unrated so no damage control is needed. You only have to focus on getting through and winning regardless how much points you lose when you don’t succeed. Winning a final hand with a small score in a Sit & Go tournament only leads to: ‘Hurray, I won, good luck next round and see you tomorrow.’

Written by
Adrie van Geffen

homepage: http://homepages.ipact.nl/~geffen

a3geffen's Hints and Pointers – pung or chow

There are quite a number of manuals on the basics of how to play a game of mahjong. The amount on strategy and tactics however is limited. Mahjong Time has asked Adrie van Geffen (a3geffen) to share his views in that territory. In the year 2011 he will publish a series of articles with hints and pointers having to do with strategy of mahjong in the different styles (except American): Hong Kong (HK); European Classic (EC); Mahjong Competition Rules (MCR); Riichi Competition Rules (RCR); Taiwanese (TW). Below part 11 – pung or chow.

One of the inevitable choices to be made by every player is the situation where you can either chow or pung a tile. Or where you can pung a tile by which you break up a chow. That is when you have i.e. 4566 in a color. When the 6 is discarded, will you pung it or let it go? And when the player on your left is discarding it, will you chow, pung or just keep a straight face?

For RCR it is quite a simple choice. Because in Riichi you will tend to keep your hand concealed and usually not much is to be gained by either pung or chow and apparently the six seems to be a safe tile for the moment, it is most likely for you to plough on and let it pass. And probably you don’t ditch it yourself for the chance that adjacent tiles are most likely still available. If not then you discard the 6 later on, knowing that at least the player who threw the first one won’t claim it.

Also EC is quite easy. A pung scores and a chow doesn’t. Since you don’t have to consider patterns for scoring, nor be troubled by a minimum of fans, you just go pung and get on with it. Unless of course you are only two tiles away from making mahjong: get a (right) tile from the wall, discard the 6 and wait for the winning one to be discarded or self drawn.

When you’re in a HK game you are probably going for all pungs, which will give you the needed 3 fan, or going for a half flush or better. In the first case making a pung is obvious. But when playing the second option all kinds of considerations come to mind. When discarded and the only thing you can do is pung, then you will probably do it. You probably have other tiles of the same color (why would you play for half flush otherwise?) so every tile in the color helps. Besides that you still can switch to all pungs later on. The chance that the other players are aiming at all pungs as well is fairly high and you will have one in the pocket. But if you have a 7 or 8 in the same color it might be much better to chow. Hope for possible pungs on 4 and 5 by other players will be diminished and the chance they become available is increased. Besides that you can still pung another one or get the 7 or 8 you are also looking for.

In TW there is quite a large chance you are playing for all chows, which guarantees you to get you your needed fans. All pungs and half flush isn’t that easy to get in TW style. And since you get not that many turns in a game (12 tiles extra are dealt, so three turns less) you have to be resolute with given opportunities. In general I would most likely let it pass and discard my own 6 at a given point in the game.

As often the situation gives the most worry in MCR. The vast number of patterns, in which middle tiles play a very important role, makes it tempting to do something. But a major rule in MCR is: keep your hand concealed as long as possible. But there is a lure if you can get a waiting hand for the last 6 by making a pung. That tile could be worth 6 points (last tile 4, tile hog 2). You just have to be sure you have a score of two points (perhaps all simples). Discarding the last tile is a dangerous thing in MCR and often neglected. Less experienced players, going for pungs, will not think twice discarding a tile of which a pung lays on the table. It is a chance, but a small one. As said, usually you will leave that discarded 6 untouched. Chances for getting a usable tile from the wall and get a wait with more options than just that single tile to go mahjong are much larger.

Written by
Adrie van Geffen

homepage: http://homepages.ipact.nl/~geffen

a3geffen's Hints and Pointers – Time

There are quite a number of manuals on the basics of how to play a game of mahjong. The amount on strategy and tactics however is limited. Mahjong Time has asked Adrie van Geffen (a3geffen) to share his views in that territory. In the year 2011 he will publish a series of articles with hints and pointers having to do with strategy of mahjong in the different styles (except American): Hong Kong (HK); European Classic (EC); Mahjong Competition Rules (MCR); Riichi Competition Rules (RCR); Taiwanese (TW). Below part 10 – Time.

A complete game of mahjong consists of a certain amount of hands to be played. In RCR two rounds (East and South) are played, thus a minimum of 8 hands. Other styles have a minimum of 16 hands (in MCR that amount is fixed). Playing tournaments IRL with sufficient time to play full games resulted in a long waiting time for those players that were fast and had no extra hands to play after wins by East. Organizers of tournaments weighed the pro’s and con’s and nowadays rounds usually have a set time, mostly not enough to complete a full game.

Mahjong Time has fixed time schedules in tournaments as well. A good thing for all kinds of reasons, like very big scores that cannot be beaten anymore; drop out players substituted by Jerry; temporary absence for physical needs; etcetera. These are also reasons why few tables are set up to complete a full game. By setting these time limits a new element is introduced which can lead to some annoyance at the table: the clock.

Keeping an eye on the clock, which is not very difficult for the screen tells you how much time is left, can be used in several ways. An obnoxious one is stalling. A player can wait out the full time he has available, and even more when extra time has been bought. This will soon lead to understandable and just complains. That doesn’t only happens on line but in live tournaments as well. Stalling by a Chinese player, very fast all the time but suddenly at the end, with him in the lead, ‘thinking’ for over 40 seconds to move, lead to some bickering at the table at the World Championship MCR 2010. No need to speak the same vocal language to make clear this was not appropriate behavior. And it’s not the right way to use the clock.

A better one to use the clock is, when in the lead, not to mind your own hand but discard only safe tiles. It may be completely against your natural striving for making a good winning hand, but you have to mind the bigger picture: win the game. Your fellow players won’t notice it immediately and you stay well within what is allowed. Checking the archives may reveal you defensive play but there are no ground for complaints. You have to practice for this kind of play against your gut feelings, but it may prevent you from discarding the winning tile in the last minute and lose the game with a waiting hand that just didn’t make it.

Written by
Adrie van Geffen

homepage: http://homepages.ipact.nl/~geffen