What is a Blues Scale? The best way to understand what a Blues Scale is is to first look at the Minor Scale and the Pentatonic Scale. We will keep it simple here. Let's compare the scales.
The Minor Scale is a 7 tone scale
Em Pentatonic Scale
Em Blues Scale
Take away the 2nd and 6th tones to get the Pentatonic Scale.
A diminished 5th is added to the Pentatonic Scale
Diminished - To reduce the note a half-step (one fret).
Memorize the Blues Scale pattern.
Ascend and descend through the Em and Am Blues Box Patterns.
Play through this lead-like progression that is played within the Blues Scale (Box).