Emphasis of the Letter Ra (Tafkhim) — Positions and Rules

Definition:
Tafkhim of Ra: pronouncing Ra with heaviness, tongue raised toward the upper palate. The default for Ra is Tafkhim unless a cause for thinning exists.

Positions for heavy Ra:
1. Ra with Fatha: "Rabbana", "Raheem"
2. Ra with Dhamma: "Ruziqna", "Rusul"
3. Sukoon Ra after Fatha or Dhamma: "Arsala", "Burhan"
4. Sukoon Ra after incidental Kasra (meeting of two sukoons): "Awi-rkudh" [Sad: 42] — disputed
5. Sukoon Ra followed within its word by an elevated letter without Kasra: "Qirtas", "Mirsad"

Quranic Example:
"Lord of all worlds" [Al-Fatiha: 2] — Ra with Fatha → heavy.
"Qirtas" [Al-An'am: 7] — sukoon Ra after Kasra, followed by Ta (elevated) → heavy.

Note:
If sukoon Ra after Kasra is followed by an elevated letter in the same word → heavy. If the elevated letter is in the next word → disputed, but thinning is the predominant opinion.