Black is covered hole; scale is chromatic, from DO, the chart below show one way of writing a tab notation graphically.
I use a number system, but intead of notes, the number shows which fingers have to be covering holes. 6 means all six fingers need to be down.
For the second octave, a single quote or hash mark is used: 6’
for a rare third octave, I use a double quote mark: 6"
Time:
a number followed by a space is at the base time (usually a ¼ note), no space means 1/8 note,
parenthesis: (34) means a 1/16 note or a tie
dotted note: 3. means 1/2 more than the notes regular beat, so 3.6 means dotted 1/8th, 3. 6 means dotted quarter note (3.6) means dotted 16th.
dashes/hyphens "-" means 2nd 1/4 note, or a half note, 2 dashes means 2 more quarter notes.
repeated phrases: 3 different enclosures for up to 3 repeated phrases in a song.
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I usually note the time signature and key of a song; sometimes I mention that a song should be played in the next key up (sharps) or back (flats). See comments / ideas on the page about strategies for playing.