What is the name of the note at the 4th string 10th fret?

To identify the note at the 4th string, which is the D string, at the 10th fret, it's important to understand how the guitar's fretboard is set up. The open D string, which is the 4th string, is tuned to the note D.

As you move up the fretboard, each subsequent fret raises the pitch of the string by a half step. Therefore, from the open D string (0 fret), you would move to D# at the 1st fret, E at the 2nd fret, F at the 3rd fret, F# at the 4th fret, G at the 5th fret, G# at the 6th fret, A at the 7th fret, A# at the 8th fret, B at the 9th fret, and finally to C at the 10th fret.

Thus, the note at the 4th string 10th fret is C. This logical progression along the fretboard is key to understanding how to find notes on the guitar quickly and accurately.