Watch the Every Day: Ex. 1a online guitar lesson by Andy Aledort from Kings of Blues & Rock Vol. 4: B.B. King

B.B. King is a master of blues phrasing, and the lines shown here, played over a medium uptempo swinging 12-bar blues in Bb, aptly illustrates his effortless, melodic style. The majority of the lines played here are based on the Bb minor pentatonic scale (Bb Db Eb F Ab), with brief reference on bar 10 to Bb major pentatonic (Bb C D F G).
In bar 1, a Bb sounded on the high E string is immediately followed by an expressive slide up to Bb on the 11th fret of the B string; playing two consecutive root notes in this fashion is a B.B. trademark. Essential also to the B.B. King style is the inclusion of the "B.B. box," shown here in bars 4 and 5: as the name suggests, this is a "box" position (a fixed fretboard position) wherein the root note is positioned on the B string and is fretted with the index finger. From this root note "anchor," B.B. likes to play phrases made up of either the minor or major pentatonic scale, or a combination of both.
Another signature element is the lick in bar 9, as a Cm7 arpeggio-C Eb G Bb-is articulated in swinging eighth notes over the ii (two minor) chord, Cm7.