What is the note at the 1st fret of the 6th string?

The note at the 1st fret of the 6th string is F.

To understand this, it's important to know how the guitar is tuned. The 6th string, when played open (without pressing down on any frets), is tuned to E. Each fret on the guitar represents a half step (or semitone) increase in pitch. Therefore, pressing down the 1st fret of the 6th string raises the note E by one half step, resulting in F.

This understanding of the fretboard and how notes progress in half steps is crucial for recognizing the relationships between notes as you move up and down the neck of the guitar. Knowing that the notes on the 6th string start with E open and progress through the sequence of notes on the fretboard helps reinforce your ability to identify notes in other octaves or positions.