Heaviness of Baa in "Bismillah" — Its Ruling and the Scholarly Difference

Origin of the Issue:
Baa is an Istifaal (non-elevated) letter and is by default lightly pronounced — but scholars of Tajweed discussed the baa of "Bismillah" specifically in the context of recitation preceded by "Aoodhu."

First Opinion — Absolute Lightness:
Baa is an Istifaal letter and is never heavily pronounced — its kasra further confirms lightness. This is the majority view, also held by Ibn Al-Jazari in various positions.

Second Opinion — Effect of Majestic Name:
Since baa connects to the Majestic Name "Allah" which is pronounced with heaviness, and "Allah" here is preceded by fatha (per those who posit an implied fatha) — some held that baa acquires slight heaviness from its proximity to the Name.

The Preferred Position:
Tajweed-correct: baa is light in "Bismillah" because it is a kasraed Istifaal letter — the heaviness of the Majestic Name does not carry backward. This is what most verifiers hold.

Important note:
The Majestic Name "Allah" itself is heavy when preceded by dhamma or fatha, and light when preceded by kasra — this is established independently of the baa issue.