3 Draw Rule for Blues Harmonica Playing

The 3 Draw rule for Blues harmonica playing is that on the I7 Chord (one chord) you play 3 draw (It's the B of this G B D F Chord)... the IV7 Chord you play 3' (the B-flat of this C E G B-flat Chord) and the V7 Chord you play 3" (A of this D F# A C Chord). Keep in mind that depending on the feel of the song, the 3 draw for the I7 chord can be played slightly flat (bluesy quarter tone) or at the half step B-flat if the song is really bluesy or minor.

Keep this in mind while playing... it's a common newbie error to play the 3 draw unbent on the IV7 Chord... which sounds really bad... or on the V7 Chord, which doesn't have to sound bad... mostly depending on the line you're playing (a major 6th arpeggio sounds killer... see Improvising Study 4 for more details on this)... but awkward in most cases. There are of course exceptions to this rule (phrasing being the main one... see Improvising Study 1), but it's pretty much a rule of thumb for playing. Put on a jam track and give it a try.

I7 = 3 (B of G B D F)
IV7 = 3' (Bb of C E G Bb)
V7 = 3'' (A of D F# A C)