29 rules

Ties and slurs

What is the difference between a tie and a slur, and how is each drawn?

They look alike and mean nothing alike. A tie joins two instances of one pitch into a single sounding note and is a fact about those two notes; a slur groups distinct pitches into a phrase and is a fact about a span. These rules keep the two apart, and cover the harder cases — chord ties, ties across barlines and system breaks, and curve direction.

Breaks the readingCheckable from the score alone
A rest may never carry `tie: true` / `tiedToNext: true`
A tie sustains a sounding pitch; a rest has no pitch to sustain, so tying a rest is a category error, not merely an unusual case.
Breaks the readingCheckable from the score alone
A slur must span at least two distinct notes
A slur is inherently a connective mark between two or more notes; a 'slur' with identical start and end index, or a reversed pair, is not a slur.
Breaks the readingCheckable from the score alone
A slur's first and last note must not be a rest
A slur connects two sounding notes in a legato phrase; a rest has nothing to legato-connect to or from. A phrase mark MAY visually span over an intervening rest inside its range, but its two ENDPOINTS must land on actual notes.
Breaks the readingCheckable from the score alone
A tie on the last note of a voice has nothing to tie to
A tie always resolves to a following note; a tie flag on a voice's final note is either a leftover authoring mistake or an intent to continue past a boundary the model doesn't represent (e.g. into a repeat — see tie-into-repeat-or-volta-hazard).
Breaks the readingCheckable from the score alone
A tie's next note must be the identical single pitch
A tie connects two noteheads of the same written pitch (same letter name, same accidental, same octave) that sound as one continuous note.
Breaks the readingCheckable from the score alone
A tie's two notes must match in accidental, not just diatonic step
Ties require identical spelling, not just identical sound — F#4 tied to Gb4 (enharmonically identical pitch, different spelling) is invalid; a tie must never be used to represent an enharmonic respelling.
Breaks the readingCheckable from the score alone
Chord ties must compare pitch SETS, not authored array order
A tied chord requires every notehead of the first chord to have an identical-pitch counterpart in the second chord; the order pitches were listed in when authored is not musically meaningful.
Breaks the readingCheckable from the score alone
MusicXML tie pairing must check every chord tone, not just the root pitch
Tying a chord requires ALL of its pitches to persist unchanged into the next chord; a chord tie is invalid if the chord's content differs at all — including a chord tone changing accidental with the same diatonic step.
Breaks the readingCheckable from the score alone
The public Notation API has no way to author a slur at all
Slurs are fundamental, universal notation; any authoring surface aimed at agents composing real music needs to express phrasing, not just pitch/duration/dynamics/articulation.
Breaks the readingCheckable from the score alone
Tie and slur are structurally distinct fields, never inferred from each other
A tie is a per-note boolean meaning 'sustain into the identical pitch that follows in this voice'; a slur is an index-range annotation over a phrase, agnostic to pitch identity. The two must never be inferred from one another or conflated in a single field.
Misleads the readerNeeds the rendered page
A slur must not visually overlap a dynamic marking, articulation mark, or another slur below/above the staff
When a slur shares vertical space with a dynamic or articulation mark on the same side of the staff, engraving convention nudges one or the other further away — never allows visual collision.
Misleads the readerNeeds both
A slur spanning a system break must draw a partial curve on each system
Same principle as ties: a slur whose notes fall on different engraved systems is drawn as two segments, never simply omitted.
Misleads the readerNeeds the rendered page
A slur's curve anchors at the notehead's edge, never at the stem tip
The engraved slur begins and ends close to the notehead, on the side away from the stem, with a small consistent gap — it never extends to touch or start from the stem tip. This is a distinct convention from tie curvature direction: it concerns the ANCHOR POINT (X/Y position where the curve touches), not which side the curve bulges toward.
Misleads the readerNeeds both
A tie into the next system must render a partial tie on each system, not vanish
When a tie's second note falls on a new engraved system, professional engraving draws a partial tie curving off the right edge of the first system and picks up at the left edge of the next — never simply omitting the tie.
Misleads the readerCheckable from the score alone
A tie must not be authored across a repeat sign or into a first/second ending
A tie implies the immediately next SOUNDING note in performance order; a repeat barline is a structural jump, so a note tied 'into' a repeat does not reliably sustain into whatever plays next. Standard practice never ties across a repeat sign — a pitch that must continue through a repeat is re-articulated as a fresh tied pair after the repeat resolves.
Misleads the readerCheckable from the score alone
A tie should not coexist with an articulation that implies re-attack or detachment
Staccato, staccatissimo, and accent all imply a distinct, separated or re-struck attack; tying a note while marking it staccato is usually a contradiction, unless deliberately notating a portato-like effect (which Gradus's schema has no dedicated marking for).
Misleads the readerNeeds the rendered page
A tie's curve must be placed on the side opposite the note's stem
The tie arc curves away from the stem. The primary engraving rule is actually POSITIONAL (notes above the middle staff line curve down, below curve up), and 'opposite the stem' is the corollary that holds in the common case because stem direction is itself set by the same middle-line rule — the two rules diverge only where stem direction has been FORCED for a reason other than pitch (e.g. Gradus's own SATB shared-stave stemming).
Misleads the readerNeeds the rendered page
A tie's curve must clear ledger lines and staff lines, not cross them
A tie arc must not visually intersect a staff line or ledger line it passes near; engravers nudge the curve's height/width outward specifically to clear these.
Misleads the readerCheckable from the score alone
A two-note slur over identical consecutive pitches is very likely a mis-authored tie
When a slur's exact 2-note span connects two notes of the SAME pitch, the visual result is nearly indistinguishable from a tie, and the musical effect most likely intended is what a tie represents. A slur over same-pitch notes does have a legitimate niche meaning in some traditions (a short legato re-articulation, e.g. a subtle re-bow/re-tongue), but it is rare enough that it should be flagged for confirmation.
Misleads the readerNeeds the rendered page
Chord ties must curve outward from the outer noteheads, with inner noteheads' curves kept clear of each other (the outer/inner convention)
When a chord is tied, each notehead's tie is an independent curve, not one shared curve at one direction: the outermost noteheads (highest and lowest pitch in the chord) curve away from the chord body — upward for the top note, downward for the bottom note — while inner notes' ties are nudged so no two arcs touch or cross. This is an elaboration of, not identical to, the single-note stem-opposite rule.
Misleads the readerNeeds both
Overlapping or nested slurs must be drawn at different heights to avoid visual collision
When two slurs share some notes (nested or genuinely overlapping without full containment), the outer/later slur must curve further from the staff so the two arcs don't touch or cross.
Misleads the readerNeeds both
Slur curvature must follow the same stem-opposite convention as ties, and must be voice-aware in multi-voice writing
In single-voice writing, a slur curves on the side opposite the majority of its notes' stems. In multi-voice writing, each voice's own slur must clear that voice's own stems/beams without colliding with the opposing voice sharing the stave.
Falls short of best practiceCheckable from the score alone
A long-span slur functioning as a phrase mark should be distinguishable from a short articulation slur
A short 2-4 note slur usually indicates a specific articulation/bowing/tonguing grouping (drawn close to the noteheads); a slur spanning many notes or multiple measures usually indicates an overall PHRASE MARK, conventionally a shallower, longer curve.
Falls short of best practiceCheckable from the score alone
A slur spanning multiple notes under one sung syllable (melisma) must interact correctly with the lyric/extender line, and Gradus's schema cannot currently represent this at all
When several notes are sung to one syllable, the notes are joined by a slur AND the lyric syllable is followed by an extender line (or the slur substitutes for it, per house style) spanning the same note range — the two marks must be authored consistently or the notation misleads a singer.
Falls short of best practiceCheckable from the score alone
A tie whose two notes straddle a barline is normal and must not be flagged
Ties routinely and correctly cross barlines (e.g. a half note tied into the next measure's quarter note) — this is one of the primary reasons ties exist.
Falls short of best practiceNeeds the rendered page
A tie's curvature should scale with the horizontal distance between its noteheads, not use one fixed shape for every span
Short ties are drawn as a tight, shallow curve close to the notehead; a tie spanning a longer horizontal distance is drawn flatter (and slightly deeper) so it reads clearly without colliding with anything above or below. Unlike most rules in this domain, engraving authorities describe this as a matter of hand/engraver judgment rather than a fixed numeric law.
Falls short of best practiceCheckable from the score alone
Laissez-vibrer (let-ring) ties have no representation in either schema
An l.v. tie (harp, piano pedal points, guitar, some percussion writing) indicates the note should ring without a following note to tie to — a tie 'into nothing,' conventionally a short curved stub after the final note with no destination notehead.
Falls short of best practiceCheckable from the score alone
Per-chord-tone partial ties are not representable in either authoring surface
Real engraving frequently ties only some notes of a chord while others re-attack (e.g. soprano sustains, alto/tenor restrike) — a legitimate and common voice-leading device, especially in chorale writing.
Falls short of best practiceCheckable from the score alone
Under a melisma slur, vocal beaming conventions differ from instrumental beaming, and Gradus has no vocal-specific beam logic
In vocal music, notes under a single syllable are conventionally beamed together even if that beaming crosses a metrical grouping boundary that instrumental beaming would respect; conversely, a syllable change conventionally BREAKS a beam group even mid-metrical-unit. This is governed by text underlay, not meter.

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A rest may never carry `tie: true` / `tiedToNext: true`

A slur must span at least two distinct notes

A slur's first and last note must not be a rest

A tie on the last note of a voice has nothing to tie to

A tie's next note must be the identical single pitch

A tie's two notes must match in accidental, not just diatonic step

Chord ties must compare pitch SETS, not authored array order

MusicXML tie pairing must check every chord tone, not just the root pitch

The public Notation API has no way to author a slur at all

Tie and slur are structurally distinct fields, never inferred from each other

A slur must not visually overlap a dynamic marking, articulation mark, or another slur below/above the staff

A slur spanning a system break must draw a partial curve on each system

A slur's curve anchors at the notehead's edge, never at the stem tip

A tie into the next system must render a partial tie on each system, not vanish

A tie must not be authored across a repeat sign or into a first/second ending

A tie should not coexist with an articulation that implies re-attack or detachment

A tie's curve must be placed on the side opposite the note's stem

A tie's curve must clear ledger lines and staff lines, not cross them

A two-note slur over identical consecutive pitches is very likely a mis-authored tie

Chord ties must curve outward from the outer noteheads, with inner noteheads' curves kept clear of each other (the outer/inner convention)

Overlapping or nested slurs must be drawn at different heights to avoid visual collision

Slur curvature must follow the same stem-opposite convention as ties, and must be voice-aware in multi-voice writing

A long-span slur functioning as a phrase mark should be distinguishable from a short articulation slur

A slur spanning multiple notes under one sung syllable (melisma) must interact correctly with the lyric/extender line, and Gradus's schema cannot currently represent this at all

A tie whose two notes straddle a barline is normal and must not be flagged

A tie's curvature should scale with the horizontal distance between its noteheads, not use one fixed shape for every span

Laissez-vibrer (let-ring) ties have no representation in either schema

Per-chord-tone partial ties are not representable in either authoring surface

Under a melisma slur, vocal beaming conventions differ from instrumental beaming, and Gradus has no vocal-specific beam logic