How many syllables does くの字点 affect?  is the "double or multiple repeat marker" in vertical writing. Given that it can be used to repeat two _or more_ syllables, how do you know how many preceding syllables to repeat? Is it just a matter of memorization? For example (usingto represent the symbol in horizontal writing below): is easy to understand because it is a word I am already familiar with. However, if I read and wasn't familiar with the word for repeatedly, I may incorrectly read it as and not . I realize this is a stilted example, but I'd like to nip any possibility of confusion down the line by understanding the mark completely from the start.

It is a matter of memorization.
You must already be familiar with the word or phrase to read it properly the first time.

However, because other marks for single character repetition already exist, you can be sure that you'll have to repeat at least two characters.

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