Ties

A tie is a curved line that connects two notes of the same pitch.  A tie indicates that the first note should be held for its own value plus the value of the note to which it is tied.  The second note is not sounded.

In the example above, the G on beat 3 of the measure is not sounded, but the G on the second half of beat 2 is held for the duration of both Gs:  the equivalent of one full beat.  Consider the same rhythm notated differently:

You will notice that the first example is actually easier to count, because you can see where each beat in the measure falls.  In the second illustration, beat 3 falls in the middle of the G, and is therefore not as easily distinguishable.  The first example is the preferred notation.

Ties may also occur over barlines.  Consider the following example:

There is no limit to the number of notes that may be tied together.  It is possible to have a note that is held over many measures.