I confess that before a day or two ago (in q questionnaire item for @BanjoBen) I had never heard of the Nashville Number System. I HAVE, however, heard of and used a system of Roman numerals to designate chords/intervals that are independent of a specific key.
These sound like very similar systems with very similar objectives, are they the same?
I see online articles that compare the two, which I will read, but thought I’d check with this group as well.
Thanks in advance!
That’s what it is.
Was aware, but never saw this. Thanks Mark. Now all we need is a nice little primer on concert pitch, and how it applies between different keyed instruments. 
The beauty of the Nashville Number System is that someone can indicate the key at the beginning of a tune, or even signal a key change in the middle of a tune, by calling out the key or by holding up a number of fingers, and as if by magic, everyone is in step and in key.
Although the key has changed, and the actual chords have changed, the chord numbers remain the same. It requires some memorization and a little math in your head, on the fly. I understand the concept but I can’t do it. I’m told it gets easy after using it for a while.
I witnessed it in action several times today during a jam I attended. They’d call out keys and use the numbers mostly to figure out which chords to use; sometimes before or after the song, they’d discuss it and refer to particular chords by numbers, not the chord names. They’d start a song and the singer realized it wasn’t in his range, so he’d yell out a new key and everyone just went along and it sounded great. A bunch of freaks I tell ya. Music nerds. Yeah, one day, that’ll be me.
Just FYI, these guys were playing mostly in the keys of G, A, Bflat, and C. Once in D I think.
After a while it’s actually easier to use the numbers. There’s some memorization involved, but really, you’ll mostly use it for the 1-4-5 chords. So, for example:
1 - 4 - 5
G - C - D
A - D - E
Bb - Eb - F
C - F - G
D - G - A
You’ll get to the point (if you’re not there already) where you can hear which one of those chords are being changed to. You may not even know which key the song is in, but you can hear the relative chord changes and know “Oh, that just changed to a 4.” Not all of us are blessed with perfect pitch like Ben. That’s why he makes the big bucks. 
As far as the original question, the reason they call it the “Nashville” number system, is because all the Tennessee hicks couldn’t read roman, but as long as both hands were visible they could count. (To ten, at least) so they renamed it. The systems should be exactly the same. I’ve seen both, and just assumed it was just fancier to use Roman (a la Rolex) I’ve heard that the name “Nashville” number system is a misnomer, because it actually originated in classical music in the 1500s, (around then, anyway) but that probably would have been Roman numerals
It originated in the Nashville studios with the studio musicians who mostly could not read music, but didn’t need to. No one wants to read Roman numerals. We’re American. We read Arabic.
There is much more to the NNS than writing the numbers. Within the system is communication for stops, diamonds, walks, inversions, etc. You can do that with Roman numerals, but your paper ends up looking like a chicken walked through wet ink.
I just use RN because they are easier for me to type…
This is the best thing I’ll read all day. 
Arabic ARABIC ? For goodness sake don’t tell Donald. He wants America to be GREAT AGAIN. Weird I always thought American’s were GREAT.
Turns out, the Arabic number system is as follows: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 etc.
Oh, and Americans are great (well, some of us are anyway 
)
America is in a sad, sad state of affairs. Read about the abortion laws that were just passed in NY. It actually made me a bit nauseous.
We have too many of our own political issues over here right now. I have no desire to head down that road Jack.
Me neither
It’s a painful one. Pray for us.
Just cause I care about you Jack, when you say you are nauseous, you are saying you nauseate others. I’m a grammar snob. I talk good see
My other favs include “I could care less”, orientated, irregardless, safety deposit box, and ending one’s sentences in prepositions like “where are you at?” When called out on this one, the original speaker is then usually motivated to correct his statement or question such as “where are you at a%% h@&e?”. My favorite though is Winston Churchill’s rebuttal to this rule - “that is something up with which I shall not put”.
I actually tried to explain why this is wrong once. I finally gave up. They wore me down to the point that I couldn’t care less.
I yam what I yam.