About 4 months in learning Japanese and almost done with Genki I and I’m finding there are some words in Japanese that can take several different kanji with the same pronunciation and meaning. Examples: 上る/登る、降りる/下りる. My question is, are there any rules to determine which kanji to use when? Are there subtle differences in the meaning of the word if you use a different kanji or are they just personal preferences?
I understand this exists because the native Japanese words were already in use when the kanji were imported from China and then subsequently associated with those words. But after having spent so many years learning Chinese where, for the most part, one character has one fixed reading, this is a bit confusing for me.
My biggest challenge now is remembering that Chinese and Japanese are two distinct languages and throwing all the rules I learned before out the window. There are still many times when I read a word in Japanese and immediately think of the Chinese pronunciation, especially if it’s a Chinese word (ex. 結婚する = jiehun suru), then it takes a second for my mind to put it into Japanese before it comes out of my mouth. 