What is Hai-Koritsu? Tile Efficiency Fundamentals Explained for Beginners

What is Hai-Koritsu (Tile Efficiency)?

Hai-Koritsu (牌効率) is the concept of choosing discards to reach tenpai most efficiently in mahjong. It aims to maximize acceptance tile count and reach tenpai in the shortest path.

“Hai-koritsu” means “efficient use of tiles” and is one of the most important concepts in mahjong fundamental techniques.

Detailed Explanation of Hai-Koritsu

Three Basic Principles of Tile Efficiency

Three principles of tile efficiency:
1. Maximize acceptance tile count
2. Prioritize changes to good waits
3. Keep tiles with future potential

Basic Metrics of Tile Efficiency

Priority for Isolated Tiles

Discard order (worst first):
1. Honor tiles (guest winds)
2. Terminal tiles (1, 9)
3. Near-terminal tiles (2, 8)
4. Middle tiles (3-7)

Usage Examples

Real Game Situations

Example 1: Efficiency Awareness

"Considering tile efficiency, discard :9s: before :1m:"
"Ryanmen is better tile efficiency than kanchan"

Example 2: Practical Judgment

"This shape has poor efficiency, break it up"
"Prioritize efficiency for quick tenpai"

Example 3: Advanced Conversation

"That discard was a tile efficiency mistake"
"Beginners should learn tile efficiency first"

Specific Examples of Tile Efficiency

Basic Tile Efficiency

Hand: :1m::2m::3m: :4p::5p: :7s::8s::9s: :1m::3m: :7s::9s: :1z:

Discard candidates:
1. Discard :1z: → Correct, isolated tile with no future
2. Discard :1m: → Wrong, leaves penchan
3. Discard :9s: → Wrong, leaves penchan

Conclusion: Discard :1z: for best tile efficiency

Complex Tile Efficiency

Hand: :2m::3m::4m::5m::6m::7m: :4p::5p::6p: :3s::5s: :1z::1z:

Choices:
1. Discard :2m: → Creates 3-sided wait, but loses sanshoku
2. Discard :7m: → Creates 3-sided wait, keeps sanshoku
3. Discard :5m: → Creates 2 ryanmen, maximum acceptance

Conclusion: Discard :5m: for highest tile efficiency

Related Terms

• Uke-ire: Number of effective tiles
• Shanten-suu: Distance to tenpai
• Tegawari: Change to good wait
• Tamenchan: Result of tile efficiency
• Koritsuhai: Tiles to discard first

Common Mistakes and Points to Note

Points Beginners Often Mistake

1. Only thinking about yaku

   • Tenpai before yaku
   • Prioritize tile efficiency

2. Keeping too many honors

   • Process guest winds early
   • Especially isolated honors

3. Keeping penchan

   • Penchan is worst shape
   • Should process early

4. Only looking at current acceptance

   • Consider future acceptance increase
   • Prioritize good wait changes

Basic Tile Efficiency Patterns

Processing Isolated Tiles

Value of Taatsu

In order of quality:
1. Ryanmen wait (8 tile acceptance)
2. Kanchan (4 tile acceptance)
3. Penchan (4 tile acceptance)

※Penchan has poor change potential

Practical Tile Efficiency Techniques

5-Block Theory

Ideal composition:
- Sets × 3
- Taatsu × 1
- Pair × 1 (head)

Build hand with these 5 blocks in mind

Value of Consecutive Forms

Balance of Tile Efficiency and Points

Priority by Situation

Yaku and Tile Efficiency

Maintain efficiency while considering yaku:
1. Tanyao system → Wide acceptance
2. Toitoi system → Narrow acceptance
3. Chiitoitsu → Special efficiency

Improving Tile Efficiency

Practice for Beginners

1. Identify isolated tiles

   • Find isolated tiles first
   • Practice discarding in order

2. Calculate acceptance

   • Start with simple shapes
   • Build counting habit

3. Apply in practice

   • Think before discarding
   • Gradually increase speed

Advanced Tile Efficiency

Advanced players also consider:
1. Information from opponent discards
2. Remaining tiles in wall
3. Balance with point situation
4. Efficiency combined with defense

Pitfalls of Tile Efficiency

Cases Requiring Caution

1. Handling dora

   • Don’t keep just because it’s dora
   • Discard isolated dora early

2. Handling yakuhai

   • Isolated yakuhai has low value
   • Consider after becoming pair

3. Late game efficiency

   • Consider remaining tile count
   • Prioritize genbutsu acceptance

Conclusion

Tile efficiency is the most important concept in mahjong fundamentals, the thinking for efficiently reaching tenpai. Beginners should start by discarding isolated tiles early and being conscious of acceptance tile count. Mastering tile efficiency enables reaching tenpai faster and more reliably, ultimately improving win rate. Keep in mind that “mahjong is a game of probability,” and practice discards conscious of tile efficiency.