Riichi Mahjong with Hakui Koyori - How to Play and How to Watch

[@holorelics]

More detailed explanations and caveats not mentioned in the video here.
This video goes through everything very superficially, if you're interested in learning how to play, you should take a closer look at the rules beforehand.
Mahjong is a game where every action has pros and cons, which is why even pro players can argue on what's the best thing to do in a lot of different situations, making it a very interesting game.
As an intro, I learned to play Mahjong in 2020, played in all sorts of Mahjong clients through these years (Mahjong Soul, Sega MJ, Tenhou, Saki (PSP), Touhou Mahjong, Clubhouse Games and more), got to Master in Mahjong Soul in both 4 player and 3 player as my highest ranks.
=== East-Only (Tonpuu) and East-South (Hanchan) ===
Games of Mahjong are usually played either in East-Only or East-South.
East-Only means everybody gets to be the dealer once, so the game lasts for 4 rounds plus any dealership extensions.
East-South everybody plays as the dealer twice.
In most competitive scenarios, you'll see people playing East-South games, since having more rounds means there's less chance involved and more room to comeback, but they're also much longer.
The Hololive tournament is played in East-Only.
=== The wall of tiles ===
Out of the 136 tiles, not every tile is used every game. 14 tiles are reserved and set aside called the dead wall, from where the dora indicators come from. This means you can't guarantee that what you need will be available.
At the middle of the screen in Sega MJ there's a number indicating how many tiles are left until the end of the round.
=== 4 Groups and a pair ===
There's one yaku called Chiitoitsu or Seven Pairs that is an exception to this rule. You can win a round by having 7 pairs instead of making a traditional hand, but generally speaking it's a deceptively hard hand to complete and not worth much if you don't include dora in it.
=== Shanten ===
Sega MJ is very convenient to have a Shanten counter, as it's an easy way for viewers to see how close are they to finishing the hand. When you get your starting hand and you have 5 Shanten or higher, it's quite hard to win the hand, since that's a lot of improvements your hand needs to take to get there. 3 or 4 is the average starting amount.
It can already be hard to finish a 5-shanten starting hand, finishing it before the other 3 players do it is even harder.
=== Dealership and Winds ===
Every round a player is assigned a direction, East, South, West and North. The East player is the dealer of the round, the round after it rotates so the South player becomes East, and so forth.
Being a dealer, other than being the first one to draw and discard, grants you a lot of different traits.
1 - If you win the round, you get to repeat the round and be dealer again. This is very useful if you're behind in points and will make dealers play more aggressive than normal.
2 - You score ~50% more points than normal. A hand worth 8k by a non-dealer is worth 12k, making that aggressiveness even more profitable. When the dealer declares Riichi, it's very common to have the rest of the table fold immediately.
3 - If another player wins by Tsumo, you pay double what the others pay. A 8k tsumo will have the dealer paying 4k of those points.
Other than dictating who is the dealer, this distribution of cardinal directions also determine the players' winds.
The wind tiles only have value as a triplet if it's the player wind or the round wind.
In East-Only games, the round wind will be East. In East-South games, after East-4 the game goes to South-1, where South will be the round wind.
=== The Yaku Requirement ===
The most common mistake of beginners is trying to win a hand without having a Yaku. It's possible to reach Tenpai with a "dead hand" that cannot win the round except through extreme luck (winning off the last tile in the wall or through a Kan).
If you don't call Pon or Chii, no matter what you can always Riichi at the end of your hand to get Riichi as your Yaku. Ideally you'd pick up other Yaku along the way to make your hand bigger, but you can't go wrong with that.
If you decide to open your hand and call tiles from other players, several Yakus cannot be obtained anymore, you shouldn't call tiles without having a plan.
There's a crazy amount of different Yakus and trying to memorize and recognize them can be tough, but some happen every game while others I haven't seen once in thousands of Hanchan matches.
=== Furiten ===
Another common mistake is the Furiten mechanic. The reason the tiles each player discarded are neatly separated on the board is because of them being relevant for Furiten. When you have a hand in Tenpai, you'll have a list of tiles that you're waiting for to win usually between 1 and 3 different tiles, although it could be more in extreme circumstances.
If any of those tiles you're waiting for is in your discard pile or they got Pon/Chii/Kan by another player (they're still considered your discards), you're in Furiten and you cannot call Ron to win off somebody else's tile, only by drawing it yourself.
This mechanic exists so other players can take defensive decisions. If a player calls Riichi, every tile they discarded so far is considered safe. Discarding the winning tile is extremely punishing as you'll have to pay the full amount of points, a lot of the time it's a game losing situation. It can be better to let them Tsumo and share the payment or draw the hand.
There are dozens of strategic techniques and theories derived from the Furiten mechanic for more advanced players.
=== Calculating Points ===
Not going to go deep into this subject, but generally speaking each Yaku has a "han" value, usually 1 or 2. Each dora also gives you 1 han each. You count up your han and that will guide you towards how many points you'll get. There's a lot more to it, but this gives you a general idea.
The progression of points you get per han is exponential to a certain point, going 1k→2k→4k→8k→8k→12k→12k→16k→16k→16k→24k→24k→32k for a non-dealer.
Because of this rapid growth, getting hands in the 5k~8k range is quite valuable and not as hard as it seems, although not trivial either.
Anything above 12k is very rare, with 32k being the famous Yakumans.
=== Riichi and Dealership Streaks ===
Another thing about Riichi not mentioned is that you must deposit 1k points to declare Riichi. Whoever wins the round will receive those 1k points in addition to whatever they win.
Even if nobody wins that round, the 1k will stay on the table until somebody wins a hand. This is why you'll see +9000/-8000 on screen, for example.
When you get additional rounds due to the dealer winning their hand, you increase the Honba counter in the middle. For every repeat round, whoever wins gets an additional 300 points.
=== Tile Efficiency ===
The basic strategy in Mahjong is Tile Efficiency. Choosing the correct tile to discard to have the best odds of ending up with a Tenpai hand with a good wait. Tiles like 3+4 are very strong, since you have 8 tiles to finish the sequence for a 234 or 345, on the other side 7+9 is a bad wait, since you must draw one of the four 8's to finish the sequence.
Because of this, the tiles that are hard to use are usually discarded first, like Honor Tiles (you need a triplet) or edge numbers (1s and 9s).
There are lots and lots of books about Tile Efficiency, covering all sorts of weird combinations of tiles and what should you do to maximize your odds and it's a huge part to getting past the beginner stage of the game. There's no need to go super deep into it before playing, but having an idea on what a good discard is can be very useful.
=== On the Tourney itself ===
With the tourney format, it will definitely involve a lot of luck. Which is good for an exhibition tourney, as literally anybody in the 8 players involved can win the tourney. Being better at the game can get you faster to Tenpai and be able to not deal other players winning tiles more easily, but you still need some luck to actually win a hand in this amount of rounds, and if you don't win a hand, you can't win a tournament. Thanks for reading~

[@KnightCrown]

Respect for goin into such details

[@nishadabanana7706]

Very useful, thank you for the explanation!

[@SSRB_Botandyn_446]

SALUTE!!! This really helps to at least grasp the flow and rules of Mahjong! Thank you so much!