Kanji

ON vs. Kun: General Rules

Knowing whether to use the ON or the Kun readings of a kanji character depends on the context of the character and recognizing (through practice and review) which word is actually being used. However, there are a few general rules that may help you know when to go with the ON or the Kun:

1. Words that require ON readings next to never contain hiragana. This is because the ON readings are based on the Chinese pronunciations of the characters and the hiragana alphabet is a Japanese invention. Words with ON readings can—and most often do—contain more than one kanji character, however.
   
   
2. If a word contains a mixture of kanji and hiragana, the kanji character is mostly likely pronounced with a Kun reading.
   
   (*These two rules do not mean that words made up entirely of kanji characters are by default pronounced with ON readings. Some words that consist entirely of kanji characters are pronounced with Kun readings, although they are far less frequent than all-kanji words requiring ON readings. The only way to tell these apart is to memorize all of the readings of a character and evaluate the context.)
   
   
3. Just as words and concepts borrowed from Western languages are written in katakana, words and concepts borrowed from the Chinese language are written in kanji and are pronounced with their ON readings.
   
   
4. ON readings for a kanji character are most often one syllable in length, although two-syllable ON readings do occur fairly frequently.
   
   
5. Kun readings can range from one syllable to five syllables in length for a single kanji character.