Idgham Kabeer

Idgham falls into two categories:

Major Idgham (Idgham Kabeer)

This is when a voweled letter meets another voweled letter such that they become one doubled letter.

In Hafs's transmission from 'Asim, only a handful of words contain this type, all in the "identical letters" category, such as:

the word ta'manna in ﴾قَالُواْ يَا أَبَانَا مَا لَكَ لاَ تَأْمَنَّا عَلَى يُوسُفَ وَإِنَّا لَهُ لَنَاصِحُونَ﴿ (Yusuf: 11) — originally "ta'manuna", but the voweled Noon merges into the following Noon, becoming "ta'manna". It is pronounced with Ishmam or Ikhtilas (a partial vowel-gesture of the lips indicating a hidden damma).

the word atuhaajjoonni in ﴾قَالَ أَتُحَاجُّونِّي فِي اللَّهِ وَقَدْ هَدَانِ﴿ (Al-An'am: 80) — originally "atuhaajjoonani".

and ﴾مَا مَكَّنِّي﴿ (Al-Kahf: 95) — originally "makkananee".

There are no examples of Major Idgham in Hafs's transmission for the "homogeneous" or "close" categories.

Minor Idgham (Idgham Sagheer)

This is when a silent letter meets a voweled letter such that they become one doubled letter of the same kind as the second — such as merging Taa into Taa in ﴾فَمَا رَبِحَت تِّجَارَتُهُمْ وَمَا كَانُٰا مُهْتَدِينَ﴿ (Al-Baqarah: 16). This is the type covered in the following sections, in its three forms: Mutamathilayn, Mutaqaribayn, and Mutajanisayn.

Complete and Incomplete Idgham

Complete Idgham

The merged letter disappears entirely — both in essence and quality — leaving no trace in pronunciation.

Example: ﴾قَالَ قَدْ أُجِيبَت دَّعْوَتُكُمَا﴿ (Yunus: 89) — the Taa disappears completely, in essence and quality.

Another example: ﴾أُوْلَٴئِكَ عَلَى هُدًى مِن رَّبِّهِمْ﴿ (Aal-'Imran: 69) — the Noon here is completely merged into the Raa, in essence and quality.

Note: complete Idgham is marked in the standard script by removing the sukoon from the merged letter and doubling the letter merged into.

Incomplete Idgham

The merged letter disappears in essence but some of its quality remains. This occurs in four cases:

Noon before Waw, as in ﴾وَمَا لَهُم مِّنَ اللَّهِ مِن وَاقٍ﴿ (Ar-Ra'd: 34) — when the Noon merges into Waw, its ghunnah remains.

Noon before Yaa, as in ﴾مَن يَقُولُ﴿ (Al-Baqarah: 8)

Ttaa before Taa, as in ﴾ لَئِن بَسَطتَ﴿ (Al-Ma'idah: 28) — the Ttaa's heaviness (isti'la and itbaq) remains; note it does not carry Qalqalah here.

Qaf before Kaaf, as in ﴾أَلَمْ نَخْلُقكُّم مِّن مَاء مَّهِينٍ﴿ (Al-Mursalat: 20) — note the Qaf likewise does not carry Qalqalah here.