Guitar players are always bangin’ on the familiar “blues box”: the standard pentatonic scale shape. (Example 🄰, below, shows it in E minor.)
But, there are 4 other modes of a 5-note scale. Wikipedia shows them in A Minor/C Major, but we’ll continue to start from E, since we’re guitar players. Examples 🄱, 🄲, 🄳, and 🄴 show new box shapes for those 4 modes, going down from E Minor (the viii/i scale degree), to D Blues Major (the VII scale degree), to B Blues Minor (the v scale degree), to A Suspended (the iv scale degree), to G Major (the III scale degree).
In these examples, take a look at the fretting-hand fingerings I suggest. In most cases, you can stick to a friendly “1 finger per fret” pattern. But there is 1 stretch: In A Suspended, I mostly stay in the 5th position except that I stretch back with my ① to get the B note on the G string (4th fret). And there are some places where I use ② and ④ instead of the more comfortable ① and ③ and ① and ④ grips. I find this to be good exercise.
Wikipedia gives many names for the modes, based on their usage in several cultures. Note that they use “blues” not in what I consider the usual way — i.e. a pentatonic scale with an additional ‘blue’ note, the ♭5 in Minor and the ♭3 in Major scales — but to refer to modes that resemble, but are not quite the same as, Pentatonic Minor and Pentatonic Major.
Note that we use upper-case Roman numerals for major scales and chords, like G = III, and lower-case numerals for minor scales and chords, like E = i and B = v.
You might wonder why, for example, we call the VII scale, D Blues Major, a major scale — it has no 3rd (no F), so it can't really be major or minor, right? Well, (a) we have to call it something; and (b) in the key of E minor, D’s major 3rd (F♯) is present. So if you were playing in the modes of E Pentatonic Minor, but you absolutely had to play an F of some kind, it’d most likely be an F♯. So in a pinch the mode based on D is notionally ‘major’.
Similarly, the mode based on A would be ‘minor’ if we absolutely had to pick. (E Minor has C natural, A’s minor 3rd.)
In example 🄵, I show some open-position chords. These are 4-note chords that this scale generates. In a normal 7-note diatonic scale, the notes of a 4-note chord are usually the 1st, 3rd, 5th, and 7th degrees: the 7th chords. But in a pentatonic scale, we aren’t necessarily going to get those specific scale degrees for a given chord — they might not be present. In such cases, I chose the note 1 scale degree down from the expected note. For example, where there is no 3rd, I use the 2nd (see the chords based on D and A). Where there is no 7th, I use the 6th (see the chords based on D and G). For the chord starting from B, there is no 5th (would be F♯), so I went down and selected the 4th (E).
But you could make other choices!
Normally, when you’re playing your 12-bar blues and jamming in your pentatonic box, you play the i, iv, and v chords (in E: Em(7), Am(7), and Bm(7)). But those chords use some notes that don’t strictly exist in this pentatonic scale. By sticking strictly to the notes of this scale, we get what I think are more interesting chords.