I remember reading somewhere that open D is sometimes recommended to beginning guitarists because you can play all of the major chords just by sliding your finger up and down the fret board. (I'm pretty sure that Tommy James [of "and the Shondells" fame] explains in Me, the Mob, and the Music that he learned guitar this way [though I read that book about four years ago, so I could be mis-remembering].) And while this is true, I think it's a bit lazy from a musician's perspective. I think that it's important to understand the logic behind the shapes - to know which notes constitute a particular chord. So while the single-fingered-chords are indeed a feature of open D tuning, that's not really a reason why I like it so much. (Though my position on this may change if I ever start learning slide guitar in open D.)
There are three main reasons why I like open D tuning so much. The first is that the chords seem a lot closer to-gether. I'm not sure if this is actually true, but it seems easier to transition from D major to A major in open D tuning than it does in standard tuning. You just switch two fingers and move down a fret.
An-other reason is that you don't really have any barre chords (unless you choose to use the single-fingered-chords technique), and I tend to find barre chords uncomfortable. This may be because I'm a self-taught guitarist and have poor form, but I find that using a lot of barre chords quickly becomes tiresome. There's too much wrist bending. Open D tuning doesn't have any of that.
And finally, I like open D tuning because the notes are in order within the chord shapes. In standard tuning, the notes are all over the place.
For E major, the strings are E, B, E, G#, B, E (root, fifth, root, third, fifth, root).
.png)
C major is E, C, E, G, C, E (fifth, root, fifth, third, root, fifth).
.png)
.png)
There really isn't any consistency of note positions between chord shapes. But in open D tuning - using only the middle four strings, which is what I do - the chord shapes have the constituent notes in order, even if you use inversions.
D major is D, F#, A, D (root, third, fifth, root [an octave higher]). You could play the outer most strings too, since they're both tuned to D. And, in fact, you could just play all open strings.
.png)
The first inversion of A major is C#, E, A, C# (third, fifth, root, third [an octave higher]).
.png)
In my experience, having different notes of the triad on the bottom (mixing thirds with the more regular tonics and fifths) can make for more expressive chord progressions. While inversions with the third on the bottom are possible on a standardly-tuned guitar (if you use the bottom four strings, they're the same shapes as some mandolin chords), they're much easier in open D tuning.
Aside from standard tuning's being a standard, the only superiority it has to open D - as far as I can see - is how easy it is to form suspended chords. It's really easy to transition from, say, D major to Dsus4 to Dsus2. Though I don't think that suspended chords are often a concrete part of any chord progression. I see them more as embellishments than anything else. The same goes for chords with extra notes on the top. Like an E major with an added G# on the high E string. So as far as straight chords go, open D tuning is the best. Although I'm still more familiar with standard tuning.
And, aside from all of the music theory stuff, I like open D tuning because it gives me new shapes to play around with. Because I'm still learning open D, I don't fall into conventional patterns, which is a possibility when I'm using standard tuning.
---&---
