The missing notes on a regular bluesharp.

If we take an harmonica in the key of C:

• D# is missing in the low octave.
• D#, F#, Bb are missing in the middle octave.

If we take the 1rst and 2nd positions, these notes correspond to the following degrees:

• D#: minor third in 1rst position.
• F#: flat fifth in 1rst postion.
• Bb: minor third in 2nd position and flat 7th in first position.

If we focus on the blues scale, we can notice that there is only one missing note in the middle octave in 2nd position but this note (minor third) is very important.

In 1rst position, there are so many important notes missing that the middle octave is unplayable (in blues). This explains why most 1st position blues are played on the low and high octaves.

Until quite recently, these missing notes were a major problem for playing jazz or other elaborated styles of music and contributed to confine the harmonica to the blues.

In the 80s, Howard Levy (an american piano and harmonica player) started to popularize a new technique, called Overblow, which allows to get the missing notes on regular bluesharps. For the last decade many young players have followed this path and open new territories to the harmonica. The Overblow technique being quite difficult to master, some manufacturer and customizer designed new instruments (based on the Richter tuning) allowing to play the missing notes more easily.