Personal Riichi Mahjong Notes
Index#
๐โโ๏ธ Introduction#
I recently got into Riichi Mahjong ๐
It’s a very fun game for me as I enjoy TCG games (I played Hearthstone & Shadowverse previously) and Poker, and it felt like Riichi Mahjong has the elements of both of them that I enjoy.
This note will be an evergreen note for myself to abstract the idea that I have on Riichi Mahjong to keep improving my gameplay. And also this will be beginner - intermediate level and will contain lots of mahjong terms.
๐ Glossaries#
- ็ญ : Pinzu (Circle)
- ่ฌ : Manzu (Character)
- ็ดข : Souzu (Bamboo)
- Tenpai : One tile away from valid hand
- Kanchan : Middle wait (e.g.: 35 waiting for 4)
- Penchan : Edge wait (e.g.: 12 waiting for 3)
- Ryanmen : Side waits (e.g.: 45 waiting for 3 or 6)
- Genbutsu : Safer tile being kept to push for tenpai while sacrificing a little bit of speed (usually leftovers honor or 19 tiles)
- Mawashi : Trying to push a hand to tenpai / win while still keeping it relatively safe
๐ฏ Tile Efficiency#
This section will cover the idea of pure tile efficiency with no regards to score nor defense. In short, the fastest way to get into good tenpai
Lots of these I didn’t realise at first due to concentrating on not having too many pairs (as we only need 1 pair + 4 sets in Riichi / Mahjong). But often times having stacked suits actually have higher chances of improving / completing the hand especially early on.
Yonren#
4-Sequence Shape
3456็ญ is better than a 345็ญ + 6่ฌ. It can accept:
- 1: 1-3 kanchan and 456 sequence
- 2: becomes 23456 with 3 sided wait 1,4,7
- 3: pair of 3 with 456 sequence or possible ippekou
- 4: 34 ryanmen with 456 complete shape
- 5: 56 ryanmen with 345 complete shape
- 6: same as 3
- 7: same as 2
- 8: same as 1
234567 (6 tiles) are all good draws, while 18 (2 tiles) are suboptimal
Whereas 345็ญ + 6่ฌ can only accept 45678่ฌ where only 57 (2 tiles) are good and 468 are suboptimal (3 tiles)
Hence, don’t want to break a 3456 shape for 6 on another suit unless it gets to tenpai
Nakabukure#
Bulging middle sequence
4556็ญ is better than a 456็ญ + 5่ฌ. It can accept 34567 for good shapes (ryanmen)
Whereas 456็ญ + 5่ฌ can only accept 46่ฌ for ryanmen. It also gives good chances of getting ippekou
3-Sided Waits#
- 34567 waits for 257
- 3334 waits for 245
- to be updated… there are lots of these and identifying these are key to increasing win rate
Isshanten States#
Isshanten is the state where we are 1 tile away from tenpai. This is the the part where the tile acceptance count to improve or reduce the shanten is the smallest, so we want to focus to maximize this as much as we can to get the fastest tenpai possible (and preferably still good waits)
There are 4 Isshanten Shapes from Weakest to Strongest
Surplus / Floating Tile#
2 Ryanmen Blocks with 1 Floating Tile that doesn’t contribute to acceptance (usually genbutsu).
Waits: 69M and 14P (16 tiles max. total)
Complete#
Added pair to one of the Ryanmen Block so it increased tile acceptances
Waits: 679M, 14P, 8S (20 tiles max. total)
Headless#
Does not have a pair, 3 completed blocks
Waits: 6789M, 1234P (28 tiles max. total) ps: getting 69M or 14P isn’t ideal because it leads to tanki wait
Headless with Ankou#
Same as Headless, but one of the completed blocks are Ankou (triplet)
Waits: Same, but now getting 69M or 14P can still gives 2-sided waits by discarding 8S ps: No pinfu if draws to 78M or 23P
Kutsuki#
Best Isshanten shape, 3 completed blocks + 1 pair and 2 floating tiles
Waits: 56789M, 123458P (40 tiles max. total)
Kutsuki with Yonren and Nakabukure#
Better Kutsuki that leads to better waits in tenpai, 42 Total Tiles max. for Tenpai
Waits: 1234567M, 123458P (42 tiles max. total)
โ๏ธ Offense#
Open vs Closed Hand#
Good rule of thumbs on when to start opening:
- 2-shanten
- 3+ Hans (from the yaku, doras, and akadoras)
- It’s all last and the score needed is sufficient to get the placement desired (lock 1st place / chase position)
This is why looking / memorising the score table is very important because otherwise we might be locking 3rd or 4th unnecessarily when we can actually get 2nd. Also don’t forget to keep track of the Riichi Sticks and Honba to take into account when calculating the score needed
Push vs Fold vs Semi-Push (Mawashi)#
I personally don’t have set rule on when I push / fold / mawashi, but these are the things that will be used as gut feeling:
- Am I Isshanten / Tenpai?
- Am I far behind and little rounds left?
- Am I a dealer?
- Am I against a dealer? (1.5x score if we deal into dealer, often overlooked when I was noob)
- How dangerous does the opponent hand look?
- How good is my hand?
- How dangerous is the tile I need to discard to push? (Discard reading is especially important here)
- Is the score worth the risk?
Misplays will happen as it’s hard to take into account so many factors and limited to 5+20s timer when playing online, better player can make these decisions faster and more accurately
๐ก๏ธ Defense#
Suji Tiles#
In Riichi, there is a Furiten rule where a player can’t Ron on a set where it contains 1 or more tiles that they have discarded previously. For example, if a player reaches tenpai while waiting on 34็ญ, they are not allowed to Ron if they have previously discarded 2็ญ or 5็ญ
This concept can then be used to decide on a SAFER and less useful tiles to be discarded when we think the enemy has reached tenpai. This is not 100% SAFE because it’s only effective when we are defending against a ryanmen wait
For example, the player we assumed to have reached tenpai (or 100% tenpai if Riichi is called) has discarded 17็ญ. That means it’s safe to discard a 4็ญ because if the last set is 23็ญ or 56็ญ, the 4็ญ tile will be safe due to the furiten rule. This also works with middle tile of 4/5/6. Which invalidate all lines of 1-4-7, 2-5-8, and 3-6-9
The key is to keep track of the tiles being discarded AFTER tenpai (much easier if Riichi is called because the hand is locked and can’t be changed anymore and it’s 100% tenpai)
There are 3 Suji Lines of each suit, which means 9 Suji Lines in total to keep track of. From here, we can decide on which tile is less useful so we can keep pushing our hand while trying to reach tenpai ourselves.
p.s.: Good players will intentionally set suji trap when we are relying on suji too often to push for win
Early Discard Read#
Early discards gives information of what tiles do players have and the possible waits. With the assumption of people playing efficiently to some degrees, some things can be assumed.
Discarding 7 early means the player don’t have 5/6/7/8/9, because they won’t discard the 7 otherwise
This means when that player has reached tenpai AND we intend to push, 89 becomes safer for our discard push
Yaku Read#
- Honitsu / Chinitsu : Heavy discard on 2 specific suits and willingness to discard good middle tiles (especially if good shape like 45)
- Tanyao : Discard terminal tiles
- Junchan / Chanta / Kokushi : Middle tile discards (4-6) on all shapes
- Chitoi / Toitoi : Discard matching other player discards (to make faster tenpai)
Riichi Discard#
The tile being used for Riichi is especially important clue when it’s done on 10th or more discard, because that means the player has been saving this tile in his hand until the final shape. It’s either an overflow tiles from another shape like 5667 which means it doesn’t give a clue. Or it’s an upgrade (e.g. 46 getting 7 then discard 4). Generally tiles around the last discard for Riichi is dangerous and should be assumed to be the potential wait(s)
Kabe / Wall#
Keep track of the tiles that has been locked out by discards / pons. Tiles that are sandwiched are generally safer because they can’t be used for sequences. For example: 3็ญ has been Pon’d and discarded, this means the only possible way to have waits on 12็ญ are shapon / tanki wait, which are rarer and have lower score (no pinfu)
This also checks out for combination of kabe, for example 3 and 6 has ran out, it means 4 and 5 are generally safer to be discarded