 Richter tuning is designed as a compromise between diatonic melody and harmony.The lower portion of the harmonica is designed to play the tonic and dominant chords on the blow and draw respectively (in the key of C, this would be the C major and G major chords).The remainder of the instrument is tuned to, in this example, blow entirely in the key of C major, with each successive note following the sequence

and the four notes not in the C major chord arranged on the draw in the sequence

For example