And by that loose title, I'm referring to the ON and KUN readings.

I'm over halfway through Heisig's Remembering the Kanji Vol. 1, and so haven't yet touched upon Kanji pronunciations. What do ON and KUN mean and which one is used most often?

Also, what is the best way to learn them, for when I eventually finish RTK? I heard Vol. 2 isn't too effective.

Oh, and I understand some kanji have more than 1 meaning. As Heisig only teaches one keyword per character, this could be problem, right? How severe is it?

Thanks everyone, and never stop going for the goal!

Hi,
I will try to answer your question but I am sure many other people are more knowledgeable on the subject. Basically, Japan adopted kanji from China back in 800 AD or so, and with it came a set of pronunciations. Japanese people however, did not use tones like Chinese did, so they immediately stripped away the tone and just took the pronunciation as it sounded to them. Because China differentiated words with tones, Japan was basically left with tones of words that sound the same. This is the ON reading. MOST of the time you will see it in kanji compounds, as in, words with more than one kanji.

As for the origin of the KUN reading, and I might be guessing here, is that some kanji were applied to words Japanese already had, so they sound a little different, typically have more syllables, and rarely repeat themselves like ON readings. It is hard to say whether you see ON or KUN more often... Some words are always ON, some always KUN, some kanji you frequently see both readings (sometimes in the same sentence). You will get a hang of this as you go.

A big thanks, danieldesu. I don't feel so in the dark now.

The best way to learn them is in context, and through immersion. It is a very bad idea to try to learn ON and KUN for each kanji in isolation, and then try to mix and match (I tried that, oops). Rather, learn whole words, noting how kanji are read when they combine; I'm quizzing words for 2kyuu from compound-to-reading/meaning, with example sentences whenever I can find one. It's always easier to remember in context.

But that doesn't come until you finish RTK1. I've said before that RTK2 is not as good as 1, but in the sense that RTK2 is a guide, not a course. It offers some broad ways of organizing the kanji to learn them, but not a thorough, systematized way like 1 does. I would recommend at the very least looking at the pure and semi-pure groups at the beginning of RTK2 and learning the example compounds he puts forth. That's six or seven hundred words, and it will open up reading to you a lot. The rest you can determine how useful it is depending where you are in your studies.

But again, all in time-- first get the meaning & writing down. Meanwhile, keep up the good work!

Also, I was going to reply to your other question but didn't have time this morning. To me, RTK gives you a way for your brain to differentiate the kanji. Before, I could never remember the difference between 年　午　牛 and the like, but now they all make sense. I don't have to think of the keyword every time (in fact, I have generally poor ability to guess a word's meaning just using the keyword), but I don't regret learning that way and my Japanese has improved 10-fold since I finished RTK (a few months ago).

As noted above, the ON readings are the Japanese versions of the way the Chinese scholars/missionaries who brought the kanji to Japan read them. China has many different dialects so, depending on when and where a particular importer came from, many kanji ended up with more than one ON.

It's like showing a drawing of a dog to a frenchman, a german, and an englishman -- each will tell you how THEY pronounce "dog."

The KUN readings started out as the equivalent of the keywords we use with RtK -- they're what each kanji meant in Japanese. Just as a single kanji can have multiple nuances in english, it can have more than one way to say it in Japanese. And once the kanji began to be used to write Japanese, instead of just Chinese Buddhist scriptures, the number of KUN for many kanji grew.