The black line is your finger # 1 (index) that is use to block all strings. (or just use a guitar capo)
* this notication can change between chords diagram you will see in other books / web pages *
The other numbers in circles are your 3 other fingers (middle - 2, ring - 3, pinky - 4)
2 fr means that you start to play this chords at the second fret.
This post was edited by Kafir on Dec 4 2012 07:15pm