Small Tsu Patterns?

I searched and couldn’t find a relevant thread and also searched Google hoping to find a similar Tofugu article like the one for Rendaku, but alas, nothing.

Is there ever a specific pattern that I can detect to determine whether a sound will be truncated with a small tsu in compound kanji?

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I’m not sure I understand your question - are you wondering if a small tsu would ever be found at the very end of a word? Generally not, though you may see a small tsu at the end of sound effects or interjections, such as あっ!

Or are you asking about a small tsu in the middle of a word (e.g. 学校がっこう)? This only happens in certain cases - before kana that begin with k, s, t, or p. (source: Wikipedia)


Something like がく and こう. がくこう is twice the same (or similar) sound, so it becomes 学校.

That’s all I have for now.


I’m at work and so I don’t want to give some in-depth answer without the convenience of an IME, but I do just want to clarify the wording on this bit

You’re not truncating words. You’re truncating the particular on’yomi reading of that kanji. The word is the full thing.

As a more general answer to your question, it’s similar to what Kazzeon said (and of course Saruko’s link says what I’m saying). K-sounds will get it with other K-sounds. A normal tsu will “shrink” in front of a lot of sounds. K-sounds, H-sounds (h then turns to P-sound), T-sounds (including tsu + chi), S-sounds. Generally nothing with dakuten though (B-sounds, G-sounds, D-sounds, etc). After a while, you get a feel for it, and become surprised when it doesn’t happen in some words.


There’s also the common 分からない -> 分かんない and 入るな -> 入んな contractions.
But I guess that’s a different topic.


First of all, there is no truncation. Gemination, which is what I assume you are talking about, is the doubling of a consonant sound.

This article has some information on gemination in Japanese that might be helpful to you:

And, yes, there are limitations on what can be geminated.


Thank you @Saruko. The second part of your answer was what I was trying to convey in my original question. It was early, so my brain was finding it difficult to articulate my question clearly.

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Thanks good reply. Also, I didn’t mean truncating the word, I meant truncating the sound. I didn’t describe it properly and kind of thought as much as I was typing the OP… it was early.

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I guess there are patterns but I personally never read about them. They start to become second nature after some time. As of right now one example could be that 〜つ + か/き/く/け/こ sometimes becomes a double consonant (っ). There are probably loads of exceptions and other examples as well. Such as く + こう = っこう a lot of times. 格好、学校

月刊(げつ - げかん)
出勤 (しゅつ - しゅきん)
節句 (せつ - せく)
滑稽 (こつ - こけい)
結構 (けつ - けこう)

Also, not an expert, take everything with a grain of salt. Just felt like replying for some reason :sweat_smile:


An interesting regular exception is when the first two kanji in a word are a word by themselves, while the third kanji builds further based upon those.

For example, take architect: 建築家.
建築 means architecture, and the 家 makes it an architect.
However, since 家(か) is kind of a suffix to 建築(けんちく), the result does not become けんちっか, but けんちくか


I really like this response. Thank you, that actually makes loads of sense. I can see it becoming very natural once I get exposed to it more often.


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