Chords in Key

[TomJoad]

If I wanted to blow harp with a song I'm writing and the chords are

Bm |F#m| G | D | G | D | A | A |

does that mean I need a D Harp?

 

[JonR]

If I wanted to blow harp with a song I'm writing and the chords are

Bm |F#m| G | D | G | D | A | A |

does that mean I need a D Harp?

Yes.

If you were playing a blues in D, then you would choose a G harp.
But the presence of Bm and F#m suggests to me that this isn't blues!

 

[snowscientist]

I just wanted to thank JonR and Quill for explaining in a way that turned on the lightbulb as to why the chord sequence in a particular key is the way it is. The stacked 3 note notation really opened my eyes, and I think I actually understand it. Thank you to all in this excellent thread. I have been sort of playing guitar for 2 years and really did not understand this until after reading this thread. Awesome....