"Sensei"

This is a small point. If I address a letter like this:

"Dear Smith Sensei"

it reflects a certain distance. Perhaps I do not know Smith Sensei too well.

If Smith Sensei were my own Sensei, I would be more likely to write:

"Dear Sensei"

If I used his surname, he might feel that I was being too formal.

But I would never write:

"Dear Bill (or Sam, etc.)"

That would be too informal (in a traditional sense).

When you are close enough to address your sensei as "Sensei," you are lucky!

Respectfully,

Charles C. Goodin