The intro is really the entire concept of this song. What you will
have is a standard Em chord, played with some bass notes.
The key here is to play the Em barred, when usually you don't. By barring
the Em chord, you can hit the third fret on the Low E string with ease.
If you listen closely, you can see how the theme just repeats itself.
I've included video for the intro because the rhythm is a little tricky,
as with almost all Johnny Cash songs.
Intro
Video
Verse 1
Notice once again that the intro theme is repeating, until the seventh
and eighth measures. There, you are just playing a standard Am chord,
into the G, and then the F#.
Bridge
The bridge is reminiscent of the intro, so there's no need for further
explanation.
Verse 2
This verse is only a little different. The first two measures are that
repeating theme again. Then, you will just transition to the G chord,
Am chord, and then the Am7 chord. Notice that at the end of this verse,
you will play a quick Em into a C. Do this by playing the standard Em,
without barring. This will be a little easier I think in using basic
chord structure.
