Do native speakers think of 固い・堅い・硬い as homophones, or as the same word? Japanese dictionaries often give distinguish among meanings for homophonous words with related meanings that have different kanji representations, such as: * (see, for example, the entry for these words) * * * My intuition is that all three forms of are really "the same word" in a native speaker's mental lexicon, and that a native speaker will choose a given representation from in writing so as to provide added meaning. Is my sense correct here, or do native speakers actually regard as three different words?

It is exactly as you suspect. It is totally illogical to consider , for example, to be three different words and here is why.

Whenever you are dealing with a kun-reading word, you need to remind yourself that it existed when Japanese was merely a spoken language. We had no way of writing or even . All we had was the sounds "katai". Then we encountered the Chinese and the rest is history.

The vast majority of homonyms in Japanese are found in words of Chinese origin.