It is the simplest Chinese character in the language due to consisting of only one line.
In the Kangxi Dictionary, there are 60 characters (out of 47,043) to be found under this radical.
[1] 一 is also the 1st indexing component in the Table of Indexing Chinese Character Components predominantly adopted by Simplified Chinese dictionaries published in mainland China.
The only stroke in radical one, known as 橫/横 héng "horizontal", is called 策 cè in the eight principles of the character 永 (永字八法 Yǒngzì Bāfǎ) which are the basis of Chinese calligraphy.
As an isolated character it is one of the Kyōiku kanji or Kanji taught in elementary school in Japan.