一
one
yī
What does 一 mean?
一 (yī) is the Chinese number 'one' — a single horizontal stroke, the simplest character in the language. But it's also the trickiest HSK 1 character because its tone changes depending on what follows it (tone sandhi): 一 is yī when alone or at the end of a phrase (第一 dìyī 'first'), yì (fourth tone) before first, second, or third tones (一杯 yì bēi 'one cup,' 一年 yì nián 'one year,' 一本书 yì běn shū 'one book'), and yí (second tone) before another fourth tone (一个 yí ge 'one [item],' 一定 yídìng 'definitely'). Don't write the tone change in pinyin for dictionaries — yī is the citation form — but pronounce it correctly.
A separate reading yāo is used when reading out digits one by one (phone numbers, room numbers): 一一八 = yāo yāo bā. Always followed by a measure word before a noun: 一个人 (one person), never 一人.
Character breakdown
one (a single horizontal stroke — the simplest hanzi)
Memory hook: One stroke = one. The simplest character in Chinese is the number one.
Example sentences
我有一个哥哥。
Wǒ yǒu yí ge gēge.
I have one older brother.
spoken
请给我一杯水。
Qǐng gěi wǒ yì bēi shuǐ.
Please give me a glass of water.
polite
我们一起去吧。
Wǒmen yìqǐ qù ba.
Let's go together.
spoken
他是我的第一个老师。
Tā shì wǒ de dì yī ge lǎoshī.
He's my first teacher.
neutral
Common phrases with 一
Don't confuse 一 with
二 is 'two' as a number in counting (一, 二, 三) and dates / floors. But for 'two of something,' Chinese uses 两 (liǎng), not 二. 一 (one) takes any measure word; 二 doesn't usually combine with measure words for quantity.
壹 is the formal / financial form of 'one,' used on banknotes, checks, and contracts to prevent forgery. 一 is the everyday form. You'll see 壹 written on Chinese currency.
FAQ
Acquire by listening
Hear 一 in real Chinese, not in a flashcard.
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