In America at least, Haiku are commonly taught to students as poems having 5, 7, then 5 syllables, when in actuality, they have a structure of 5, 7, then 5 on. The NaHaiWriMo site explains what an on is, but I'm having trouble wrapping my mind around it.

I thought I could look for a tool online to determine the number of on in a given input, much like this syllable counter; however, I'm having further trouble, since "on" is a common word in the English language. Does such a tool exist? Or would it even be possible to create a tool to consistently determine the number of on in a language other than Japanese?

  • 1
    There are two on google but I do not know anything about onji. Have you tried these? haikusyllablecounter.com
    – SFWriter
    Feb 23, 2018 at 1:13
  • Thanks, @DPT. This doesn't seem to count on, despite its other neat features.
    – zr00
    Feb 23, 2018 at 5:04

3 Answers 3


You can try Japanese Transliteration which will take English words and *transliterate them into Hiragana, which you can hear spoken (lower right hand option). This means it will show you the Hirigana spelling that most closely approximates the sounds of the English word. You can decide how good it is by listening to the Japanese speaker pronounce the Hiragana. For me, most are close but definitely not sounding like English.

As your article says, there is no definition of on in English, the number of on can only be computed by converting the sound to Hiragana, and then recognizing (from the Hiragana site) how many on are represented in the Hiragana spelling.

In Hiragana, either one or two glyphs represent a single syllable to be uttered in the Japanese language. Scroll down in the site to get a complete list.

Because it refers to sounds, you might be able to portray the sound of an English word in Hiragana, but not every English sound can be represented in Hiragana.

For example, the words "chick" or "bat" both turn into two syllable words in Hiragana, sounding like "chi-ku" and "ba-ta", because all Hiragana syllables end in a vowel sound.

I would also say, whatever you write in English trying to adhere to this strict definition of on will likely be rejected as not real Haiku; readers and critics won't care about such technicalities and will count English syllables, which is apparently what the inventors of Haiku were aiming to do in their own language, capture syllables of the Japanese language.

  • Interesting, especially that last paragraph. Do you have any kind of sources or links to something I could read further regarding modern readers and critics or the (potential) intent of the inventors of Haiku? It seems to contradict other things I've read.
    – zr00
    Feb 23, 2018 at 15:31
  • I don't, I read the wikis provided (by you on on) and Haiku and Hiragana; it just seems clear to me reading that: on is either one or two glyphs in Hiragana, they do not stand for letters, they stand for syllables in the Japanese language; even the two-glyph ones stand for a single sound. If Haiku are defined as 5/7/5 on, then that was their intent. It is my opinion everybody taught in school Haiku is 5/7/5 syllables will reject an English Haiku with a three syllable line, written with the excuse that the closest Hiragani translation would be 5 syllables. Good luck with the tool.
    – Amadeus
    Feb 23, 2018 at 16:03
  • Thanks for your help. Accepting this answer as it not only answers the actual question asked, but gets to deeper concepts underlying the question as well.
    – zr00
    Feb 26, 2018 at 17:09

An on is a feature of the Japanese language that does not exist in English. Counting something that does not exist makes no sense.

For the same reason, whatever is written in English and called a "haiku" is not a haiku in the Japanese sense of the word. American haiku poet Cor van den Heuvel writes:

A haiku is not just a pretty picture in three lines of 5-7-5 syllables each. In fact, most haiku in English are not writtten in 5-7-5 syllables at all -- many are not even written in three lines. What distinguishes a haiku is concision, perception and awareness -- not a set number of syllables. A haiku is a short poem recording the essence of a moment keenly perceived in which Nature is linked to human nature. As Roland Barthes has pointed out, this record neither describes nor defines, but "diminishes to the point of pure and sole designation." The poem is refined into a touchstone of suggestiveness. In the mind of an aware reader it opens again into an image that is immediate and palpable, and pulsing with that delight of the senses that carries a conviction of one's unity with all of existence. A haiku can be anywhere from a few to 17 syllables, rarely more. It is now known that about 12 -- not 17 -- syllables in English are equivalent in length to the 17 onji (sound-symbols) of the Japanese haiku. A number of poets are writing them shorter than that. The results almost literally fit Alan Watt's description of haiku as "wordless" poems. Such poems may seem flat and empty to the uninitiated. But despite their simplicity, haiku can be very demanding of both writer and reader, being at the same time one of the most accessible and inaccessible kinds of poetry. R. H. Blyth, the great translator of Japanese haiku, wrote that a haiku is "an open door which looks shut." To see what is suggested by a haiku, the reader must share in the creative process, being willing to associate and pick up on the echoes implicit in the words. A wrong focus, or lack of awareness, and he will see only a closed door.

In English, a haiku is not defined by a specific number of on, syllables, linesk, words, sounds, or whatever, but by its content.

Forget about the on.

  • +1 for "Forget about the on. It does appear that the tool is possible, based on Amadeus's answer, though it's probably a pointless tool.
    – zr00
    Feb 26, 2018 at 17:10

Or would it even be possible to create a tool to consistently determine the number of on in a language other than Japanese?

No, it isn't. Or rather, it is possible to count something consistently, but if you're looking at a language like English, there is no agreement about what "on" would correspond to.

As the Wikipedia article you linked to mentioned, the equivalent general linguistic concept is the "mora" (from Latin, plural "morae"). As far as I know, there is no general agreement about how to count morae in modern English. See the Linguistics SE question How would a haiku look in English using morae?

There are specific theories that use the term "mora", or similar concepts, to describe certain rules in English that seem to be related to syllable "weight", but because of the differences in how English and Japanese use consonant sounds, it's not really directly comparable to the Japanese concept.

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