In zhuyin fuhao (bopomofo), "ㄧ" is equal to "i" or "yi" in Hanyu pinyin. I have noticed, when displayed on my computer, even with very complete fonts, I see a vertical line (similar to "|"), but when I see a picture of this symbol (e.g. see here: http://www.omniglot.com/writing/zhuyin.htm), I see a horizontal line (similar to "一").

  • Does this symbol have two forms? When are they used?
  • What is the correct direction for this when writing horizontal text? Vertical or horizontal?
  • Is my computer turning it the wrong direction if I see a "|" (vertical line) when typing horizontal text?
  • If horizontal is correct, how do I type it horizontal?

4 Answers 4


Sorry for my misunderstanding of your question. Actually, because 注音符号 is abandoned in the mainland(it still remains in the dictionary), and is mainly popular in Taiwan, so I am not familiar with that system.

I searched 注音符号 on the Wikipedia, and I found the answer.

依照中华民国教育部规定,注音符号的“ㄧ(yi)”在直写时要写成“—”、而横写时写成“丨”。台湾国语教育一般使用直写,故在台湾一般人并没学过“丨”,在横写时亦写成“—”。中国大陆由于废除中文直写,故字典等采用的注音符号字型,都固定造成“丨”的形状。下为瓶子两字的排列方法: enter image description here

It says, the Ministry of Education of R.o.C specified that "|" was used when the characters were aligned horizontally, and "一" was used when the characters were aligned vertically. However, in the practice of education in Taiwan, usually only "一" is used and thus Taiwanese doesn't know the "|" form. In the mainland, only "|" is used.

  • My question does not refer to tone symbols (四声). I was referring to the character used in zhuyin fuhao (注音符号) to express words with the "-i" in the pronunciation.
    – Village
    Commented Jan 5, 2012 at 2:35
  • @Village I just realized that and edited my answer, sorry.
    – Huang
    Commented Jan 5, 2012 at 2:48
  • @Village In pinyin system, we use the letter "i". I don't know what your "vertical line" is.
    – Huang
    Commented Jan 5, 2012 at 2:53
  • I am talking about zhuyin fuhao (注音符号), not hanyu pinyin (汉语拼音).
    – Village
    Commented Jan 5, 2012 at 3:07
  • @Village OK, I think now I answered your question.
    – Huang
    Commented Jan 5, 2012 at 3:58

Just some additional information related to how to input the horizontal version:

In Unicode, the code point for "BOPOMOFO LETTER I" (0x3127) takes the vertical form. There's not horizontal version in the 'Bopomofo' section in Unicode.

But a further search showed me that "BOPOMOFO LETTER I" is rendered either horizontal or vertical in different fonts. In Huang's post, I see “ㄧ(yi)” as horizontal in my browser, however, we I copied it to word, it became vertical.

I checked the fonts installed on my computer, and MingLiU, Arial Unicode MS will render it as horizontal, Simsun will render it as vertical.

If you want it to be definitely horizontal or vertical, the wiki article Huang cited may provide a solution: “—” ("EM DASH" , 0x2014) for the horizontal version, and “丨” (0x4E28 ,in the CJK Unified Ideographs section) for the vertical version.

  • Now that I'm using another computer and a different browser, “ㄧ(yi)” is now rendered as a vertical bar.
    – fefe
    Commented Jan 6, 2012 at 5:50

Huang has a great answer.

Additional info is that in Taiwan when printing the bopomofo to the side of the character, the first tone "一" is usually not printed at all. It is considered as the "default" tone. The other three and the neutral tone are printed out.

  • 1
    So, how do I type "ㄧ" horizontally? When I see it on my screen, it is vertical, like "|", but I usually work with horizontal text.
    – Village
    Commented Jan 5, 2012 at 9:46
  • You could do it Taiwanese way and not print it at all? Commented Jan 5, 2012 at 14:21

The answer is extremely simple:

Always use the horizontal form in vertical text, and always use the vertical form in horizontal text. That's truly all there is to it. How do I know for sure? I've read several of the actual Zhuyin promotional documents (in Chinese) from the pre-Taiwan Republic of China. So yeah, I'm pretty darn sure.

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