To slur or not to slur: that is the question
In my published books I have always devoted a great deal of attention to phrasing, because I believe that phrase marks, or slurs, provide syntactical clarity to music and thus serve as indispensable performance guidelines for the pianist.
Many writers and publishers omit slurs in printed music, especially music written for early-level pianists. These publishers may do this because they feel that slurs clutter the page and make it appear more difficult to play. I believe, however, that the presence of slurs makes the music easier to play. Slurs reveal the inner structure of the music by depicting the music's division into musical "sentences." The Harvard Dictionary of Music defines phrasing and articulation as "terms used to describe clear and meaningful rendition of music (chiefly of melodies), comparable to an intelligent reading of poetry."
A slur also indicates that the notes it encompasses are not individual entities, but instead are part of a coherent group of tones that should be played with a sense of connectedness, or legato, with no discernable separation between them. From a pedagogical perspective, one obvious advantage of including phrasing in early-level piano music is that it encourages students to learn the notes and articulations simultaneously, rather than separately, enabling the teacher and student to concentrate at once on giving meaningful shape to a melody.
In the filmed presentation What Is An Interval?, Leonard Bernstein describes a musical atom not as a single note, but as an interval consisting of two notes. He reasons that one note alone sounds merely like an unconnected sound floating in space, whereas two notes immediately form a relationship that can be heard. When students play groups of related tones, such as those within a phrase, they should ideally be taught to articulate them in a manner that suggests a relationship. Slurs or phrase marks provide visual evidence of that relationship.
I have served for many years as an adjudicator of student composition contests. Rarely, however, do I see slurs depicted accurately, if such marks appear at all. The following examples provide guidelines regarding the use and placement of slurs in written music, and they should prove valuable to students and teachers alike.
Slurs should begin and end on the center of a notehead, without touching the notehead. This gives clarity to the start and end of the phrase. Slurs should not be placed on barlines or in other vague areas that make defining the phrase difficult.
The stems of the notes determine basic slur placement. In phrases where the notes have upstems, place the slur under the noteheads.
In phrases where the notes have downstems, place the slur over the noteheads.
In phrases consisting of both upstem and downstem notes, place the slur over the notes.
If a phrase consists exclusively of whole notes, imagine where the stems would be located if the notes were changed to half notes. Then apply slurs using the criteria above.
For extremely long phrases, the slur may be placed over the notes, instead of under, regardless of stem direction.
If the slur must begin from a stem, the slur should start midstem, slightly to the right of the stem. If the slur must end on a stem, it should end mid-stem, slightly to the left of the stem.
If a slur continues from one staff to the next staff, angle the end of the slur on the first staff, and angle the beginning of the slur on the second staff. If the slur is under the first staff, it should continue under the second staff. Similarly, if the slur is over the first staff, it should continue over the second staff.
When a slur begins and ends on the same note, it could be mistaken for a tie. In order to avoid confusion, move the slur to the stem side of the notes.
A slur should include all the notes of a tie, both at the start and the end of a phrase.
When slurs start or end on notes containing performance articulations, the slurs should occur outside the articulations.
Fermatas should always be placed outside a slur.
Computer notation programs such as Finale and Sibelius typically follow these rules by default, but a user of these programs will still have to make minor adjustments in certain situations. In my college classes and private studio, in order to ensure that my students master the art of music notation, I insist that their submissions always be accomplished by hand, in pencil; not with a computer program. A knowledge of the principles outlined in this article, along with practice at drawing slurs by hand, will help a young composer write music with clarity and precision.
All of the rules stated above are found in the Essential Dictionary of Music Notation by Tom Gerou and Linda Lusk (Alfred Publishing Co., Inc.). For these and other rules of slurring and notation, I highly recommend this excellent resource.