Open your mushaf to Surah Al-Fatiha and look at the little word “al” (ال), the Arabic word for “the”. In al-hamdu you hear the lam clearly, but in ar-rahman it seems to disappear. This is not a printing mistake. It is one of the first tajweed rules every reader meets: the rule of the sun and moon letters.
In this guide we explain the sun and moon letters in simple English, show you how to recognise them in the mushaf, and share easy ways for children and adults to practise at home.
What are the sun and moon letters?
Arabic makes a word definite by adding ال (alif and lam) to the start of it. What happens to the lam depends on the first letter of the word that follows. The 28 letters of the Arabic alphabet are split into two groups of 14:
- Moon letters (al-huruf al-qamariyyah): the lam is pronounced clearly.
- Sun letters (al-huruf ash-shamsiyyah): the lam is not pronounced; it merges into the next letter, which is doubled with a shaddah.
The names come from two famous examples. In الْقَمَر (al-qamar, the moon) the lam is clear, and in الشَّمْس (ash-shams, the sun) the lam merges into the shin.
Lam qamariyyah: the moon letters
When ال comes before one of these 14 letters, you pronounce the lam with a sukoon, clearly and without merging:
ء ب ج ح خ ع غ ف ق ك م ه و ي
Scholars of tajweed gathered them in a short phrase to make them easy to remember: ابْغِ حَجَّكَ وَخَفْ عَقِيمَهُ (ibghi hajjaka wa khaf ʿaqeemah). Every letter in this phrase is a moon letter.
Examples from the Quran:
- الْحَمْدُ (al-hamdu)
- الْعَالَمِينَ (al-ʿalameen)
- الْمُسْتَقِيمَ (al-mustaqeem)
- الْكِتَابُ (al-kitab)
- الْفَلَقِ (al-falaq)
This is called izhar qamari, the “clear pronunciation of the moon letters”. In most printed mushafs you will see a small sukoon on the lam, a visual reminder to say it.
Lam shamsiyyah: the sun letters
When ال comes before one of these 14 letters, the lam is silent and the next letter is doubled:
ت ث د ذ ر ز س ش ص ض ط ظ ل ن
A traditional line of poetry helps students remember them: the first letter of each word is a sun letter.
طِبْ ثُمَّ صِلْ رُحْمًا تَفُزْ ضِفْ ذَا نِعَمْ ** دَعْ سُوءَ ظَنٍّ زُرْ شَرِيفًا لِلْكَرَمْ
Examples from the Quran:
- الرَّحْمَٰنِ الرَّحِيمِ (ar-rahmani r-raheem)
- الدِّينِ (ad-deen)
- الصِّرَاطَ (as-sirat)
- النَّاسِ (an-nas)
- الضَّالِّينَ (ad-dalleen)
This is called idgham shamsi, the “merging of the sun letters”. In the mushaf, the lam has no sukoon and the letter after it carries a shaddah. That shaddah is your signal: skip the lam and press on the doubled letter.
A simple way to tell them apart in the mushaf
You do not need to memorise both lists before you start reading. Look at the two marks around the lam:
- Sukoon on the lam → moon letter → say the lam.
- No sukoon on the lam, shaddah on the next letter → sun letter → skip the lam and double the next letter.
Surah Al-Fatiha alone gives you plenty of practice. Al-hamdu, al-ʿalameen and al-mustaqeem use moon letters, while ar-rahman, ar-raheem, ad-deen, as-sirat and ad-dalleen use sun letters. Reading it slowly with this rule in mind is an excellent first exercise.
Common mistakes to avoid
- Saying the lam before a sun letter. Reading “al-rahman” instead of “ar-rahman” is one of the most frequent beginner mistakes, especially for learners whose first language is English.
- Dropping the lam before a moon letter. Some readers rush and say “a-hamdu”. The lam must be heard clearly.
- Forgetting the shaddah. With sun letters, the doubled letter needs a little weight. “As-sirat” should not sound like “a-sirat”.
- Applying the rule to every lam. The rule is only for the lam of the definite article ال. When the lam is part of the word itself, as in أَلْهَاكُمُ or قُلْ نَعَمْ, it is pronounced clearly.
- Pronouncing the alif in the middle of a sentence. The alif of ال is only pronounced when you start reading from that word. When it is joined to the word before, as in maliki yawmi d-deen, you move straight into the next sound.
Why this rule matters
The sun and moon letters are not only a tajweed rule; they are part of correct Arabic itself. Native Arabic speakers apply them naturally, so learning them helps your recitation and your Arabic at the same time. Because ال appears on almost every line of the Quran, getting this one rule right makes an immediate, noticeable difference to how your recitation sounds.
It is also a perfect rule for children. It is visual, it has a fun name, and kids enjoy “catching” sun and moon letters in their mushaf. If your child is still at the Noorani Qaida stage, they will usually meet this rule in the later lessons before moving into the Quran.
Practice ideas for families
- Sun and moon sorting game. Write the 28 letters on small cards and let your child sort them into a “sun” pile and a “moon” pile.
- Colour hunt. Choose a short surah, such as Al-Falaq or An-Nas, and ask your child to underline moon-letter words in one colour and sun-letter words in another.
- Listen and repeat. Play Al-Fatiha by a well-known reciter, pause after each verse, and ask your child whether the lam was heard or not.
- One minute a day. Short, regular practice works better than long sessions once a week, especially for children balancing school and Quran abroad.
Once these letters feel natural, move on to the other foundational rules. Our guide to 5 basic tajweed rules for beginners covers noon sakinah, meem sakinah, ghunnah, qalqalah and natural madd.
Frequently asked questions
How many sun and moon letters are there?
There are 14 sun letters and 14 moon letters, together making up the 28 letters of the Arabic alphabet.
Is the sun and moon letters rule only for the Quran?
No. It is a rule of the Arabic language, so it applies whenever you read or speak Arabic. That is why learning it helps both your recitation and your Arabic.
What age can children learn the sun and moon letters?
Many children learn this rule once they can read joined letters with short vowels, often towards the end of the Noorani Qaida. Every child is different, so a teacher can tell you when your child is ready.
Why is the lam not written with a sukoon before sun letters?
Because it is not pronounced. The mushaf leaves the lam without a mark and puts a shaddah on the next letter to show that the two sounds have merged.
Can I learn this rule on my own?
You can understand it from a guide like this one, but hearing your own mistakes is hard. A teacher listening to you read will catch them quickly and help you build the habit correctly.
Book a free trial class
At Telawah Academy, our teachers guide children and adults through tajweed one rule at a time, in one-to-one online classes at times that fit families in the USA, Canada, the UK, Europe and Australia. You will read, get corrected gently, and practise until each rule feels natural.
Book your free trial class today. Message us on WhatsApp: +20 10 42642933
تعلّم أحكام اللام الشمسية والقمرية مع معلم متخصص، والحصة الأولى مجانية.