The Chromatic Scale
With the inclusion of sharps and flats, there are 12 different notes within one octave as shown in the diagram.
The notes 
and 
are always on semitone apart (1 fret). The other notes are a tone apart (2 frets). Sharps ( # ) and flats ( b ) are found between the notes that are a tone apart:
This scale is called the chromatic scale and contains all the sharps (#’s) and flats ( b’s) possible. C sharp (C#) has the same position on the fretboard as D flat (Db). They are the same note but can have different names depending upon what key you are playing in. The same applies to D# / Eb, F# / Gb, G# / Ab and A# / Bb. These are called enharmonic notes. The following large diagram shows all the notes on the guitar including these sharps and flats.
Also notice that:
The 5th fret of the 6th string (A note) is the same note as the open 5th string.
The 5th fret of the 5th string (D note) is the same note as the open 4th string.
The 5th fret of the 4th string (G note) is the same note as the open 3rd string.
The 4th fret of the 3rd string (B note) is the same note as the open 2nd string.
The 5th fret of the 2nd string (E note) is the same note as the open 1st string.
These note positions are important to remember because they are the basis for tuning
