Four rules govern what happens to a silent noon or tanween depending on the letter that follows. They are the backbone of intermediate Tajweed.
Key Takeaways
- The four rules apply to a noon sakinah (نْ) or tanween based on the next letter.
- Izhar: pronounce the noon clearly before the six throat letters.
- Idgham: merge the noon into the next letter (ya, ra, mim, lam, waw, noon).
- Iqlab: convert the noon to a hidden meem before ba.
- Ikhfa: lightly hide the noon with a nasal sound before the remaining fifteen letters.
Once a beginner can pronounce the letters, the next milestone is the rules of noon sakinah and tanween — four rules that shape a huge proportion of every recitation. They look technical written down, but each is simple once you hear it.
The four rules
| Rule | What happens | Trigger letters |
|---|---|---|
| Izhar | Noon pronounced clearly | The 6 throat letters |
| Idgham | Noon merges into next letter | ya, ra, mim, lam, waw, noon |
| Iqlab | Noon becomes a hidden meem | ba |
| Ikhfa | Noon lightly hidden with ghunnah | The remaining 15 letters |
Learn the triggers, then practise aloud
The whole system reduces to recognising the next letter. Memorise the trigger groups, then practise on real verses with a teacher who can correct the ghunnah and timing — the parts you cannot judge by yourself.
Frequently Asked Questions
What is the difference between Idgham and Ikhfa?+
Idgham merges the noon completely into the following letter, while Ikhfa hides it partially — the noon is neither fully pronounced nor fully merged, but produced lightly with a nasal sound (ghunnah).
How do I remember which rule applies?+
Learn the trigger letters: throat letters → Izhar; ya-ra-mim-lam-waw-noon → Idgham; ba → Iqlab; everything else → Ikhfa. With practice it becomes automatic.
Is a teacher needed for these rules?+
Yes — the ghunnah of Ikhfa and Idgham, and the timing, have to be heard and corrected. The theory is simple; the sound needs feedback.
Islamic Education Editorial Team
Reviewed by verified teachers (Quran, Arabic and Islamic studies) on the Talib Alillm platform.