Mahjong What to Discard (Nanikiru) Practice: Tile Efficiency Training Drills

What Are “What to Discard” Problems?

What to discard problems (何切る/Nanikiru) are mahjong practice exercises where you select the most efficient tile to discard from a 14-tile hand (after drawing).

In mahjong, you repeatedly make the decision “which tile to discard” after every draw. This judgment ability is key to improvement, and what-to-discard problems are the perfect training method for developing this skill.

Benefits of Solving What-to-Discard Problems

• Improved tile efficiency: Learn to make discards with awareness of acceptance count
• Shape recognition: Develop ability to instantly judge good vs bad shapes
• Point awareness: Make discards considering not just efficiency, but also yaku and point value
• Faster in-game decisions: Build “patterns” through repetitive practice

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Tips for Solving What-to-Discard Problems

1. Find Isolated Tiles

First, look for “isolated tiles” that have no connection to other tiles. Isolated tiles don’t contribute to potential sets, so they’re prime discard candidates.

Priority order for discarding isolated tiles:

1. Non-valuable honor tiles (guest winds, etc.)
2. Terminal tiles (1 & 9) (can only form penchan)
3. 2 & 8 tiles (unlikely to form ryanmen)
4. 3-7 tiles (rich in ryanmen possibilities)

2. Find Bad Shapes

Penchan (12 or 89) and kanchan (13 or 46, etc.) are less efficient than ryanmen (23 or 45, etc.).

If you have ryanmen, discard the bad shapes.

3. Preserve Compound Shapes

Shapes like are “ryanmen + ryanmen” compound shapes with 3 types of acceptance: . Be careful not to break these compound shapes.

4. Consider Point Value

Don’t just think about efficiency — consider yaku and point value too. Discarding dora should be a last resort.

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Challenge the What-to-Discard Problems

Click on the tiles below to select which tile to discard. The last tile (slightly separated) is the drawn tile.

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Learning Points by Difficulty

Beginner Problem Points

For beginner problems, focus on these basics:

• Prioritize discarding isolated honor tiles and terminals
• Keep ryanmen over penchan/kanchan
• Secure a pair candidate

Intermediate Problem Points

Intermediate problems require more advanced judgment:

• Recognizing compound shapes (ryankanchan, pseudo-ryanmen, etc.)
• Discards that consider yaku like sanshoku or ittsu
• Utilizing dora

Advanced Problem Points

Advanced problems emphasize reading complex shapes and point awareness:

• Judging flush hands (honitsu/chinitsu)
• Balancing between regular hand and chiitoitsu
• Judging subtle efficiency differences

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Common Mistakes

1. Discarding Dora Too Early

Dora is worth 1 han per tile. Even with slightly worse efficiency, it’s often worth keeping until the end.

2. Holding Onto Yakuhai Too Long

A single yakuhai tile has low probability of becoming a pair. If a yakuhai is isolated and you have no other effective use, discard it early.

3. Breaking Ryanmen Shapes

Discarding or from a shape significantly reduces your ryanmen acceptance. Preserve compound shapes.

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Summary

By repeatedly solving what-to-discard problems, you’ll develop:

1. Ability to quickly find isolated tiles
2. Judgment of good vs bad shapes
3. Recognition of compound shapes
4. Selection ability with point awareness

Solve a few problems every day to develop your sense of tile efficiency. Once you no longer hesitate about “what to discard” in actual games, your mahjong has definitely leveled up!

Related Articles

• Complete Guide to Mahjong Waiting Patterns
• Tile Efficiency Basics