If you think you understand the game, but you can't go out for some reason you do not understand, skip to "Now for the tricky part." below.
As mentioned in the in-game rules, there is a Mahjong practice you can use. Don't get disappointed if you lose hard: this practice game is stuck on hard mode. The point of the practice is to figure out what you're doing. If you can win consistently on the practice, you don't need this guide.
The rules in-game explain most of how to play, including cheats (which you buy with Mahjong XP, which you get from playing a bunch of games). If you are having problems, here is a boiled down summary:
Mahjong is a 4 player game. You get a hand of 13 tiles. Each player draws a tile then discards a tile, until someone has 4 sets and a pair, or until there are no more tiles left to draw. If someone discards a tile that would let you complete a set, you can take it and discard another tile in its place. A set is a sequence (1-2-3 of the same suit, called a "chi") or three of a kind (4-4-4 of the same suit, called a "pon"; you can also get a four of a kind, or "kan", but you draw a tile to replace it and it only scores you more points in a few circumstances). Any sets that include tiles you've taken from others are set aside (displayed to the left of your hand, and visible to opponents), and can not be touched for the rest of that round. 4 sets and a pair requires 14 tiles, so that includes the tile you just drew (if you win this way, it's called "tsumo") or took from someone else ("ron" is the term for winning this way). If there are no more tiles left to draw (and the last tile drawn didn't win it), the round will end. At this point, anyone who was 1 tile away from a valid hand ("tenpai") gets points from everybody else ("noten"). 3000 points are paid to anyone in tenpai from anyone in noten, divided equally. So, 3 noten players give 1000 points each to the tenpai, 2 noten players give 1500 points each to the 2 players in tenpai, and if everyone or nobody is in tenpai, nobody gets anything.
Whoever wins a hand, takes the points from everyone else (for a tsumo or noten) or from the person whose discard they won on (for a ron). There are 100,000 points in the game; everyone starts with 25,000. A game ends when one of two things happens:
- Someone's score goes negative. (If someone else does this and you come in first, you get the Busted trophy.)
- The deal passes around to the original dealer (you) at least once for normal matches ("East only"), or twice for a Character Battle ("East-South"), and someone has at least 30,000 points. The deal passes when whoever is currently East (who "deals" and starts a hand) neither wins nor gets noten payments. The "East #" or "South #" in the center keeps track of this for you: it starts at East 1, with you dealing, then goes to East 2, East 3, and East 4, South 1 (note that the dealer is still East), South 2, South 3, South 4, West 1, and so on. "East only" matches end after East 4, once someone has at least 30,000 points; if it reaches South 1 and no one has this yet, play continues until someone does. "East-South" matches end if it is after South 4 and someone has at least 30,000 points.
There are 3 suits (called Man, Pin, and Sou), with numbers 1-9 each. (The 1 tile of the Sou suit looks different from the other Sou tiles, and the Man suit can take a bit of memorization. If you're not already familiar with Mahjong, click the link on the main Mahjong page to set your tiles to English before you play a game to get easier-to-recognize tiles.) Then there are "honor" tiles: four winds (north/west/south/east) and three dragons (white/green/red). Honor tiles, if you have any, will usually be on the right side of your hand, and can only be put into three-of-a-kinds, never sequences (i.e., one of each dragon is not a sequence).
Now for the tricky part.
It is not enough to just have 4 sets and a pair. To win (other than via noten, as listed above), you also have to have something awesome about your hand. (This is the thematic link to BvS, and why the story is that this game is a celebration of Awesome.) This is called "Yaku", and most Yaku are simply about having or not having certain things in your hand (including any sets you've taken). In most cases, you only need at least 1 Yaku, but if there are 5 or more of the dotted sticks in the center, called "Renzo" (which build up each hand the dealer wins), you'll need at least 2.
The most common Yaku are:
- No honors, no 1s, and no 9s. (Or conversely, every set and pair has at least one honor, 1, or 9 tile, and you have at least one sequence. Remember, the only way to make a set with an honor tile is three-or-four-of-a-kind.)
- At least one three-of-a-kind of any dragon, your wind (look at the top of the page while playing to see your current wind), and/or the table wind (this is listed in the center of the page). This is called "Yakuhai".
- No sequences. Your sets are all three-or-four-of-a-kinds. (The reverse - all sequences and a pair, also known as "No Fu" - is also a Yaku if you meet a bunch of restrictions: you have taken no discards except possibly the last tile, the pair is none of the Yakuhai tiles listed above, and you have to complete it with a sequence that could have been completed by one of two tiles - i.e., complete a 3-4 but not a 2-4 or a 1-2.)
- Nothing from two of the suits. (Your hand contains tiles from at most one of Man, Pin, or Sou. It can have honors, though.)
Another common Yaku is about how you play. If you don't take any discards from other players (which is called having a "closed" hand), and you get 1 tile short of 4 sets and a pair, you can declare "Reach". If you do, you're betting 1,000 points that you'll win (if no one wins, this goes into a pool for subsequent rounds), and you can't touch your hand for the rest of the round (you can only discard the tile you draw). In exchange, if you get that tile that gives you 4 sets and a pair, you get a free Yaku for having declared Reach.
The easiest (but by no means guaranteed) way to get a win is:
- Do not jump at every chance to take someone's discard. Before you take one, make sure you know which end game you are going for, and that this will help you toward that end. For instance, if you take a 1-2-3 in one suit, and a 4-4-4 in another, that can make victory almost impossible in most cases. (If you have, say, a trio of dragons, then it's okay.)
- Likewise, try to maximize the number of tiles that will make your hand better. If, say, you have 3 of each dragon (which more than satisfies your Yaku requirement), and you have 2-3-3-4 in a suit, there is one tile (another 3) which would complete your hand. If you then draw the 5 of that suit, lose the 2: a 3 or a 6 will complete your hand, which makes it more likely that you will draw or someone will discard what you need. (Don't do this at the expense of completed sets, unless you have to for your Yaku.)
- Start by discarding any winds that are neither yours nor the table's. (Again, your wind is listed up top, and the table's is in the center.)
- Discard any remaining winds, and any dragons, that you have only 1 of.
- If you have a trio of any dragon, your wind, or the table's wind, you have a Yaku. Just focus on getting 4 sets and a pair.
- Otherwise, if you have few tiles from 2 of the suits, get rid of them for the one-suit-and-honors Yaku, then go for the 4 sets and a pair. (You'll also have to discard any tiles you draw from the 2 suits you're getting rid of, to keep this Yaku.)
- Otherwise, discard any 1 and 9 tiles, and then any remaining dragon and wind tiles. Once you've done this, you'll have the no-1-9-or-honor Yaku, and can focus on getting 4 sets and a pair. (But remember, you'll have to discard any 1s, 9s, or honors you draw. Also, you can't take anything that would give you a set with a 1, a 9, or an honor.)
Beyond that, most Yaku (including "Yakuman": high scoring Yaku) are listed in the in-game rules. There are a few hidden ones. Known hidden Yaku are:
- Birth of the Cosmos - all white dragons. Only possible with cheating.
- Paa Ren Chan - if you're the dealer, and you win 8 times (including via noten), the 8th time is a Yakuman. (Not technically hidden since it's in tiny print in the rules.)
Scoring is complicated, and explained in the in-game rules. There are other special situations, such as "furiten", that are explained there and not covered here since, if you ever run into them, the game automatically does the right thing for you. If you're new to Mahjong, just focus on winning as many hands as you can, and don't worry if these situations come up or someone else wins a hand. (It is even theoretically possible to get a sense of what people are looking for from their discards, and which discards they took or skipped, and use that knowledge to prevent anyone else from going out. But if you're new to Mahjong, that might as well be RNG hate, so don't sweat it when someone else goes out before you can.)