Basics of Dorian (ii) mode on the Guitar
Dorian is the second mode of the major scale on the guitar — when the 2nd scale degree functions as the tonic. Because it centers on a minor chord (ii), it’s considered a minor key. Although this type of minor scale isn’t as common as Aeolian mode (the natural or relative minor) it does come up from time to time, so you need to look out for it.
In the same way that you renumber the relative minor, you can renumber all the modes of the major scale, starting from their tonics to reflect their unique interval structures and chord qualities. Here’s what happens to the G major scale when you reorganize its notes and chords, beginning with the 2nd degree, A, to produce A Dorian mode:
Notice how the interval structure changes from G major to A Dorian. When you start the scale from the 2nd degree, it has a flattened 3rd and 7th. Also, the Roman numerals change to reflect the new chord qualities of each degree.
Here you see how A Dorian looks on the fretboard, using the G major scale chord pattern that begins on the 6th string. In this example, you see G major first and then the same notes and chords reorganized starting on A. You can move this pattern around the fretboard and produce Dorian mode in other keys.
You can see a brief demonstration on playing G Major and A Dorian at G Major and A Dorian.
The example here is just a starting point. You can play in A Dorian mode anywhere on the fretboard by using G major scale notes and chords and centering on the 2nd degree, A.
Modes are thought of as their own scales too. You can think of the Dorian scale either as a major scale with a flattened 3rd and 7th or as a minor scale with a major 6th. Its most defining characteristic is the major 6th because minor scales usually have a flattened 6th. Having the major 6th changes how the Dorian scale sounds melodically. It also changes the chord structure.
The major 6th makes Dorian’s 4th chord major, something that doesn’t occur in a natural minor scale. The major 6th also makes the 2nd chord in Dorian mode minor with a perfect 5th, allowing for i-ii chord progressions.
Here are a few sample chord progressions based on the 2nd degree of the major scale. Numbering for both the mode and the parent major scale (the common major scale that the mode is drawn from) is included. It may be easier to work out the chord progression by number in a familiar major scale pattern first (shown in parentheses) and then renumber it according to its modal tonic.
“Oye Como Va” by Santana
i-IV in A Dorian (ii-V in the G major scale)
“Moondance” by Van Morrison
i-ii in A Dorian (ii-iii in the G major scale)
“Who Will Save Your Soul” by Jewel
i-fIII-fVII-IV in A Dorian (ii-IV-I-V in the G major scale)
“Evil Ways” by Santana
i-IV in G Dorian (ii-V in the F major scale)
“Horse with No Name” by America
i-ii in E Dorian (ii-iii in the D major scale)
In addition to using the patterns shown here, you may also find yourself playing Dorian mode while in the chord pattern that begins on the 5th string.
Here is how to reorganize the C major scale to fit with its 2nd mode, D Dorian. “Another Brick in the Wall (Part II)” by Pink Floyd has chord changes based in D Dorian in this position. You can also move this pattern around the fretboard to produce Dorian mode in other keys.
You refer to modes by their tonic pitch and Greek name. So A Dorian means the tonic pitch is A and it’s the 2nd scale degree in the major scale. If A is 2, then G must be 1 and the parent major scale. G Dorian means the tonic pitch is G and it’s the 2nd degree in the major scale.
Because mode names don’t indicate the parent major scale, you have to figure them out on your own.