Rough notes
These are some rough notes for my own personal use.
Table of Contents
Terms
- ryanmen two-sided (-56-)
- kanchan gap shape (5-7) Kanchan+ 577
- penchan edge shape (-89)
- tanki Single tile waiting to pair
- shanpon double pair wait (AABB)
- Ryankan (double kanchan = double gutter) (3-5-7)
- Pentan (penchan+tanki = edge + pair draw) 1222 waits 13
- Ryantan (ryanmen+tanki) 5556 waits 47 or 6
- Kantan (kanchan+tanki) 5557 waits 6 or 7
- Long Kanchan+ 112346 -> 123 456 (drop 1) or 111 234 (drop 6)
- Kamicha - Left
- Toimen - Across
- Shimocha - Right
- Oya - Dealer
Melding
- Do not meld if one of the two holds:
- The hand is both cheap and far from ready (2-away after melding)
- Melding significantly reduces the hand value (falls from 7700+ to 2000- = 4han to 2han)
- These lose 1 han each from melding:
- riichi, pinfu, SSK, double straight, pure straight
- Incomplete SSK, double straight is often only 50/50 for the han
- Ex: 2 dora + riichi + pinfu
- Some exceptions:
- If you can eliminate a bad wait and make the hand ready, meld!
- If you have a concealed set of value tiles, you can meld with a cheap and slow hand. (Because you can safely fold the 3 value tiles if needed)
- More exceptions:
- You are ahead of the game in South-4
- There are two or more riichi bets on the table.
- You are losing and you are the dealer
Push/Fold
- Push if two of the following conditions are met:
- Ready hand (not iishanten/1-ready!)
- High scoring hand (7700+ = 4han+)
- Good wait (2 kinds, 6+ tiles)
- Push or Fold judgement
- Iishanten, net score >=1 means push
- +1: 2 good waits, 3h(4h), 4th, t5-
- =0: 1 bad wait, (3h), vs non-dealer, t6~8
- -1: 2 bad waits, 2h, vs dealer, t9+
- By turn (do not include turn in scores)
- Turn 5- : Push score 0+
- Turn 6~8 : Push score 1+
- Turn 9+ : Push score 2+
- Value, Wait, 4th, minus: vs Dealer
- Value: 3h(4h)+, (3h), 2h-
- Wait: 2 good, 1 good, 2 bad
Riichi
- Only dama (skipping Riichi) for: bad-wait riichi-only hand by a non-dealer.
- What to do with yaku-less hand:
- Riichi if you make the hand ready.
- Don’t make it ready if you don’t riichi.
Toitoi vs. chiitoitsu
- Choose chiitoitsu in the following situations.
- There is a futile pair in your hand. (Most important reason)
- There is no pair of value tiles in your hand.
- There are three or more pairs of simple tiles between 3 and 7 in your hand.
1-away iishanten
Best to worst:
- headless+ankou (8t 28k – all good)
- sticky - 4 groups (11k 40t)
- headless (8t 28k – good: 4t 16k bad: 4t 12k)
- standard/perfect (6t 20k)
Random examples
- XXX XXX 244 778 45
- cut 2 = keep the good 778 shape
- XXX 112 899 566 45
- cut 6 = go back to 2 pairs? RB1 page 76 example is similar to this + p82
- Balance the two bad shapes
- cut 5 = perfect 2-away? And the bad shapes are balanced?
- XXX 122 788 566 45
- now we can cut 1 for perfect 2-away
- both 788 and 566 are good shapes
- not really “3 pairs” because we will finish one of 788 or 566 before going to 1-away
- 3 pair / 2 pair
- 2 pairs: keep the good shape and make a clean pair from the worst shape
- 3 pairs: keep the pair in the bad shapes and cut the pair from the best shape
- Mid/Late Riichi: tiles around are dangerous
- 445 cut 4, 3-6
- 344 cut 4, 2-5
- Suji on riichi discard not reliable
- 246 cut 6, suji 3 deals in
1334
1246
1244
1245
All these 1s are worse than isolated 3!
rms p26
KD’s challenge: Invent a situation where this rms advice applies.
Probably no:
https://tenhou.net/2/?q=1245m37s223788p11z
Probably yes:
https://tenhou.net/2/?q=1245m1227p355899s
Going for headless iishanten or not:
https://tenhou.net/2/?q=1223567m78p56789s
https://tenhou.net/2/?q=1223567m78p45789s
https://cdn.discordapp.com/attachments/584898975446859796/720982540948734002/Gentaros_tile_efficiency_course.pdf
Safety Tiles
A safety tile is something that is unlikely to dealin to other players, often an honor that has been discarded already.
The advantage of holding a safety tile is that when someone calls riichi, you can discard the safety tile and avoid dealin.
The disadvantage is you hurt your efficiency.
Some factors that impact the value of safety tiles:
- You already have 5 strong blocks, and you can keep the safety tile without sacrificing efficiency
- With a truly ideal hand shape, the drawbacks of holding the safety tile are small
- Usually this involves cutting some floater tile that is not part of your blocks
- You still might be giving up the chance to improve the hand, e.g. upgrade to tanyao, SSK, iipeiko
- You have a very bad hand
- This can actually decrease the value of safety tiles!
- The purpose of a safety tile is to counterattack when someone calls riichi
- But if your hand is very bad, there is no point to counterattack
- Instead just keep your bad blocks that will generally have safe/genbutsu such as 11p, or 12p.
- When someone calls riichi, just betatori by cutting safe tiles from your blocks
- This way you maximize the chance of getting lucky and simply completing your bad shape blocks first before someone else riichis
- You have a very good hand
- If you have guaranteed mangan, you might want to go full efficiency. A Safety tile will slow you down.
- Even if someone riichis, you might want to counterattack even with non-safe tiles
- You have a medium hand
- Here is where a safety tile might be good
- If someone riichis, you want to counterattack, but not at all costs
- So now you can discard the safety tile and have at least 1 turn to decide what to do