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The core of rhythmic notation is one sentence:
A note's shape shows a proportion, not a number of seconds.
A quarter note is half a half note and twice an eighth — how long it actually sounds is decided by the tempo (one second at ♩ = 60, half a second at ♩ = 120).
This explains the beginner's commonest question — "how long is this note?" The right answer is "it is a quarter note", not "0.5 seconds".
The system of values
| Note | Name | Relative to a whole |
|---|---|---|
| ○ | whole | 1 |
| ○ + stem | half | 1/2 |
| filled + stem | quarter | 1/4 |
| + one flag | eighth | 1/8 |
| + two flags | sixteenth | 1/16 |
The rule is tidy: each extra flag (or dot) halves the value. The whole table is therefore one principle repeated — you need only remember "more flags, shorter note".
Three necessary additions
| Sign | Function | Example |
|---|---|---|
| dot | lengthens by half its own value | ♩. = quarter + eighth = 1.5 beats |
| tie | joins two notes into one (essential across a bar line) | ♩~♪ = 1.5 beats, starting inside the bar |
| rest | a value of silence (also a proportion) | 𝄽 = a quarter rest |
The second deserves emphasis: a note crossing a bar line must use a tie, never be written as one long note — because bar lines mark the accent cycle (see metre) and must not be broken for notational convenience.
Why values are proportions rather than seconds
| If values were seconds | Consequence |
|---|---|
| changing tempo would mean rewriting the score | impractical |
| no way to notate stretching (rubato) | music would turn mechanical |
| no transmission across eras | Baroque and modern playing speeds differ (see [[concept:tempo |
Proportional notation separates structure from execution — which is why the Western system has been stable for centuries: an eighteenth-century score is still readable today because it carries proportions and relative time, not absolute time.
Diagram: the shape is a proportion, the length depends on tempo
Listen: one score, two tempos
Use rhythm to hear the identical pattern at two tempos. The notation does not change; the sounding length doubles — direct proof that "the shape is a proportion, the length depends on tempo".
Common misconceptions
- "A note shape states a specific duration." It states a proportion; the actual duration follows the tempo.
- "A whole note is always four times a quarter." In proportion yes, but the **absolute seconds depend on the
- "A long note can simply be written as one big note." A note crossing a bar line must use a tie, or the
- "A dot adds a fixed length." A dot lengthens by half the note's own value (so a dotted quarter is not a
tempo** — two different statements.
bar line's accent marking is broken.
quarter plus a sixteenth). :::
Listen in the library
All tracks from midicn-lib — inline badge is the license tier (C1 commercial / C2 non-commercial / C3 study only).
Sources
- {'时值记号以比例关系（全': '二 : 四 : 八 = 2 : 1 : 1/2 : 1/4）表示长短；绝对时长由速度决定，属记谱法通则'}
- 附点、连线、休止符与谱号体系为通行记谱规范
Used for fact-checking only; all prose is original.