Bar line in music

Barlines are vertical lines that cross staves in order to show how music is divided into bars, according to the time signature. ... It is often used to denote significant changes in the music, or to mark the placement of rehearsal marks, key signature changes, and tempo changes.

1. Where is a bar line?

Where is a bar line?

Bar Lines are written from the top of the staff (line 5) to the bottom of the staff (line 1). Even if the staff uses Ledger Line Notes, the Bar Line does not extend outside the single staff. On a Grand Staff, Bar Lines are never written “outside” the staff.