I’ve heard a lot of different ideas about Bb. I understand that Thumb Bb is good for most flat keys and the 1 and 1 Bb is necessary for when B natural comes into play.

I’ve also heard from people who prefer using thumb B flat for beginners, that for most other notes (with the exception of high F# and B natural) that it doesn’t matter which thumb you press.

So my question is, why are the fingering charts marking the rectangular thumb key as the correct thumb to play for all of the other notes if it doesn’t matter which thumb you play?

Am I making sense? Probably not. I’m a trumpet player trying to teach a flute class and I am having trouble wrapping my head around this Bb key stuff. Any help would be appreciated.