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Rough notes

These are some rough notes for my own personal use.

Table of Contents

• Rough notes
• Table of Contents
• Terms
• Melding
• Push/Fold
• Riichi
• Toitoi vs. chiitoitsu
• 1-away iishanten
• Gacha notes
• Random examples

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:

1. headless+ankou (8t 28k – all good)
2. sticky - 4 groups (11k 40t)
3. headless (8t 28k – good: 4t 16k bad: 4t 12k)
4. 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