+@node Bar lines and bar checks
+@subsection Bar lines and bar checks
+
+@menu
+* Bar lines::
+* Bar checks::
+@end menu
+
+@node Bar lines
+@unnumberedsubsubsec Bar lines
+
+
+Single bar lines are automatically placed in the music so
+there is no need to add them manually. Other types of bar
+lines are added using @code{\bar}, for example
+@code{\bar "||"} for a double bar line, or @code{\bar "|."}
+for an ending bar line. For a full list of bar lines see
+the @ruser{Bar lines}.
+
+@lilypond[verbatim,quote]
+\relative { g'1 e1 \bar "||" c2. c'4 \bar "|." }
+@end lilypond
+
+@node Bar checks
+@unnumberedsubsubsec Bar checks
+
+
+Though not strictly necessary, @emph{bar checks} should be
+used in the input code to show where bar lines are expected
+to fall. They are entered using the bar symbol, @code{|}.
+With bar checks, the program can verify that you've entered
+durations that make each measure add up to the correct
+length. Bar checks also make your input code easier to
+read, since they help to keep things organized.
+
+@c This example deliberately produces a warning
+@lilypond[verbatim,quote]
+\relative {
+ g'1 | e1 | c2. c' | g4 c g e | c4 r r2 |
+}
+@end lilypond
+
+If you compile the code in the example above, you should see a
+warning in the console output: