I noticed that some words have kanji (e.g. 其れ) that are rarely used in favor of their kana counterparts. I can not find a rule for when one is used over the other, but I think it is if the kana is much easier to write than the kanji. Is this correct? Or are there other reasons?
It's not difficult as long as you get used to each kanji. That is because it was necessary to reduce the of amount of kanji ordinary people should learn. The modernisation of Japan began at the end of Edo period, the late 19th century. In 1923, the Japanese Government announced the list of common kanji (1962 characters) to make people use less kanji.
- Don't use kanji that isn't included on the list.
- Be able to use kanji that isn't included on the list for proper nouns. However, use kana for people's name from other countries or areas except China.
(We also use kanji for people from Korea, but it was under Japan's control at the time.)
- Use kana for pronouns, adverbs, conjunctions, auxiliary verbs, and particles(助詞) as possible.
- Use kana for words from other countries or areas.
Publishers, newspapers, and printing companies followed this new standard. 6,000 kinds of kanji were used on newspapers until then.
Here are more detalis:
Thank you for your response! This makes more sense now.
By the way, kana means both or either hiragana and katakana.