I understand that 两 is used instead of 二 when dealing with quantities of two. However, my question is - why? What are the historical reasons behind this?

I looked at Wikitionary but it only had historical information for when 两 is used to mean the "tael" unit - not for its definition of "two."


8 Answers 8


The historical reason behind it is kind of surprising though. From a Chinese Characters Roots book:

两 liang etymology

The earlier form [of the character] looked like a yoke and a pair of saddles of a two-horse carriage. The initial meaning was two or double. It was also a unit to count vehicles and written as later.

That is why we have:

一辆车 ― yī liàng chē ― a car (from Wiktionary)

Where you notice in 辆 that there is the 车 character, meaning car, at the left side of the 两 character.

I assume its usage became a practical one, since as in many languages (including English), you can be more specific when you are referring to a pair of objects by using 两, instead of two objects using 二.

Here's a particular example: 二炮 (Èr pào) refers to the Second Artillery and 两炮 (liǎng pào) means two guns. So, would you request two guns from your commander or a full regiment?

  • I have to say, though, the "Chinese Characters Roots" book is not an authoritative source… Oct 29, 2015 at 0:57

This might be what you are looking for:


两, or 兩:

It's used as "pair" along with describing shoes. Noted that this is more a usage than the origin of the word.

  • I did not downvote, but the person who did probably feels you should write more of an answer here and not just give a link. Jun 23, 2015 at 12:41
  • @ColinMcLarty thanks Colin, but I am not sure what else could be provided, given there aren't alot of references
    – Alex
    Jun 24, 2015 at 19:25

In ancient received texts such as the Shījīng, the Yìjīng, and others, the primary attested meaning of liǎng 兩 is 'two'. This is specifically in reference to paired sets of things, not just any two things taken together.

In the Hàn the word begins to appear regularly as a general word for "two" or "a couple of".

As a measure word, it is used in ancient texts not only with two-wheeled carriages, but also with wooden clogs (normally two to a set) and lengths of cloth (normally two zhàng 丈 apiece). We read the measure word liàng, but there are ancient scholia that say there is no need to distinguish this word from "two" in pronunciation. A measure word is fundamentally a noun, and there are cases of nouns being read in the qùshēng — very roughly speaking, the Mandarin fourth tone.

The usage as a measure word gave rise to the sense "tael", because a tael is 24 zhū 銖; the huángzhōng 黃鍾 'type of ceremonial bell' weighed 12 zhū 銖, so twice that amount was called a liǎng "two[-fold]". So "tael" is really a derived meaning of the basic word.


I am not a native speaker, but I am answering, because I feel the previous answers explain the development of the character 兩 and not why it become popular. Native speakers please correct me. My knowledge is very limited.

@Armfoot has already explained the advantage of having different words for "pair" and ordinal "two". It remains to show why 兩 replaced 二 even in cases where it does not mean pair. From watching 武俠連續劇 it appears that in the past expressions like


were the norm.

My naive hypothesis

With the development of vernacular Chinese 個 become the most common measure word. People felt that 兩個 was smoother to articulate than 二個。

To be absolutely clear, even for me it is trivial to say 二個,二個,二個。But 兩個 seems smoother. Just like the 一 in 一個 shifts to second tone for better flow.


Use 两for easier pronunciation.


Great question!

  • 两 is unit of two-horse carriage in the Shang Dynasty (c. 1600 - c. 1046 BCE),I think it's around this time that 两 replaced 二.
  • 驷(or 乘) is unit of four-horse carriage in the Zhou Dynasty.
  • 二 can be numeral(two) and ordinal numeral(second).
  • 两 can be numeral(two) and unit of weight.

From a calligraphic perspective, the character 两 represents two people (人人) attached to some kind of vehicle or container. Thus it depicts a more accurate description of two objects or subjects, in opposition to 二 which has a purely numeric meaning.

From the phonetic point of view, it also sounds better, as it is harder to misunderstand its meaning when in a sentence. Remember that in the north of China it is very common to add the sound 'er' (儿) at the end of words or sentences, such as in "你去哪?". But the composite sound "Liǎng" is much less frequent. It is easy to imagine lots of other misunderstandings that could occur in different words, such as "erzi" ("儿子"="one child", whilst "二子"="two children").

  • I believe OP is looking for the historical reasons behinds it, and he stated that 'I understand that 两 is used instead of 二 when dealing with quantities of two' Jun 26, 2015 at 14:34
  • Sorry but the phonetic part of this answer is wrong, 儿子 means "son", and nobody in China could mistake it for "二子" which do not mean anything anyway, and would not either even using "两子".
    – gb.
    Jun 29, 2015 at 4:10
  • Exactly what I said: you can imagine that kind of misunderstanding (and many others), but no native speaker will commit it. Further: "historical reasons" are to be based on facts occuring over a time span. Unless you want someone to come with some dumb history such as: "King xxx once used the character on a letter to his wife... blah blah blah... and then everyone used it ever since" that some people are so prone to believe no matter what. The development of language is a dynamic process, not a static state happening at a single point in time. Jun 29, 2015 at 9:55

Learn Chinese Grammar 3 Time of a Day https://youtu.be/wJMoZj3as8g

For detail, you can check through youtube link

  • 二 & 兩 二
    1. a) 102 b) 332
    2. a) 20 b) 200
    3. a) 第二 b) 三點二 c) 二分之一 兩
    4. a) 兩千 b) 兩萬
    5. c) 兩個人 d) 兩隻手
    6. e) 兩半兒
    7. f) 兩兄弟 g) 兩姐妹

兩 & 二 1. 二斤 / 兩斤 2. 二尺 / 兩尺 3. 二圓 / 兩圓

  • Please don't depend on the explanation from another site or a video. Links eventually break, and then this answer will be useless. Please include enough explanation here to be useful, and provide the link to the video for more detail.
    – Don Kirkby
    Aug 27, 2015 at 5:02

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