Kanji pairs that mean and are pronounced the same by themselves

Question

I have found several pairs of kanji that are pronounced the same and mean the same when they are used individually:

• 目 and 眼
• 足 and 脚
• 木 and 樹

This especially bugs me because, in Chinese (my native language), the latter ones are almost exclusively used when by themselves.

I had a small discussion about this but we didn't really come to any conclusion other than they are used interchangeably.

I currently have a few questions about this:

• Are they be used completely interchangeably without changing meaning (not connotation)?
• Is one used more commonly than the other? I'm assuming the former ones are.
• Do they give any "feeling" such as old, formal, mystical, etc?

Remember, this is only when the characters are used individually and not part of compound words. Also ignore their usage in expressions/idioms/proverbs.

Also, I would be interested if there are other kanji pairs like this.

Answer 1

I think 眼 and 樹 are restricted in usage:

• 樹{き} refers specifically to 立ち木 according to my 漢和辞典. Once you chop it down, it ceases to be a 樹. Although a standing tree can be 木 or 樹, a wooden object can only be made of 木, not 樹.

  I also think that perhaps 樹 might seem a bit more literary or grandiose. I've mostly seen it used to refer to very large (still standing) trees in fiction.

• 眼{め} refers specifically to physical eyeballs. 目 can express that too, but it also has plenty of figurative uses that 眼 does not. For example, I believe you can write ひどいめ ("a terrible experience") as ひどい目, but it would be strange writing it as *ひどい眼.

In both cases, the simpler kanji (木 and 目) are more general and encompass the meanings of the more specific kanji (樹 and 眼).

If you'd like to read about 足{あし} and 脚{あし}, I suggest you read Tsuyoshi Ito's answer on How can I differentiate between feet and legs? .