So, I am a middle school student and have been playing piano for 5 years now, but never have I ever come across something like this. I am learning how to play "River Flows In You" by Yiruma and while reading the sheet music, I happened to come across an eighth note with a slash through the stem. I did some research and found out it was called a "tremolo" but I still find it quite difficult to understand. Could someone please explain what a "tremolo" is in a bit more detail please?

  • 1
    Play two eighth notes in that quarter note's place. It's usually done to save ink.
    – Annie
    Mar 10, 2020 at 2:47
  • 1
    Can you post a picture of the note? I think the answer and the above comments may be incorrect.
    – phoog
    Mar 11, 2020 at 4:13

1 Answer 1


This is a specific kind of tremolo called a "measured tremolo." It means repeating the same note a steady, measured rate.

When a quarter note has one slash through the stem, you play two equal notes in its place, so a quarter note with a slash means to play two eighth notes. When that stem has two slashes though the stem, you play four equal notes in its place.

Here's is an excerpt from Alfed Brooke flute method that illustrates the idea (he refers to them as "abbreviations" which is not a term I have seen used anywhere else).

enter image description here

Looking at the image, it may appear that the rule is different for half notes, because one slash through the stem of a half note means four eighth notes. The slash is generally viewed as indicating the beam(s) that would connect the new note values, a half note with one slash indicates that a half note's worth of time should be filled with the equivalent number of eighth notes (which is four). If the note already has a flag or beam, the slashes indicate additional beams; so, for instance, an eighth with one slash is interpreted as two sixteenth notes, and a sixteenth with two slashes would be interpreted as four 64th notes.

Note: in percussion music, three lines on a stem is used to indicate an unmeasured role.

  • 3
    No, the rule is always the same: regardless of the note in question (quarter vs. half vs whole), the slash indicates how to subdivide the beat note. That is in N/4 time you subdivide a quarter note by the number of slashes. Mar 10, 2020 at 12:08
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    In general use, the existence of 3 slashes is considered to be a normal (unmeasured) tremolo regardless of the note length Mar 10, 2020 at 12:14
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    @CarlWitthoft As you describe it, the rule only applies in quarter meters. Surely, you wouldn’t start playing duplets (or sixteenths) if you encountered a dotted quarter note with one slash in a 6/8? The amount of slashes indicates the amount of flags the notes that should be played will have. (So a dotted quarter note with one slash in a 6/8 indicates three eighths.)
    – 11684
    Mar 10, 2020 at 23:32
  • And Peter, regardless of who is right, at the moment your explanation seems to be contradicted by your example image, if not for your “exception” at the end. Unfortunately, you would need an exception for the rule as you describe it for each kind of note; I’m sure you would agree a whole note with a slash above it doesn’t indicate two half notes for example. And consider my example of a dotted quarter note.
    – 11684
    Mar 10, 2020 at 23:36
  • I have fixed the answer to incorporate these comments. Thank you.
    – Peter
    Mar 11, 2020 at 3:39

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