Furigana: Usage and application


I've been learning Japanese with Memrise's program (for about 6+ months at 2
hours a week on average) and have managed to learn all the hiragana
characters. They don't teach katakana (I guess they assume that all words
using katakana are English cognates that I'll automatically understand what
they mean?) and move straight to kanji.

This is where I struggle, especially with characters that combine multiple
kanji into one. My understanding is that less common kanji are accompanied by
furigana (hiragana that are placed in small print over kanji to help others
pronounce the character), but I can't quite understand whether or not a word
is, by standards, "uncommon" and if I should devote as much time to words like
these where I'm not expected to remember how to pronounce them.

How can I better assume which words will be paired with furigana without
personally experiencing these words on the streets?




First of all, what is "common" or not "common" has a clear definition in terms
of readings; by extension, words could be defined to be "uncommon" if they are
written with characters whose readings are not "common".

The "common" readings are those defined in the list of 常用漢字 _jōyō kanji_. Most
of them are ( _on_ and _kun_ ) readings for a single _kanji_ : The list of
_jōyō kanji_ contains 2136 characters with one to eight readings (see 下 or 生)
per character. It also contains 116 words consisting of _jōyō kanji_ , but
with readings that cannot be obtained from the "common" readings of the
individual _kanji_.

(Note that this definition of "common" may or may not agree with the actual
frequency of readings in a large enough sample of written Japanese. I would
expect there to be a strong correlation, though.)

The _jōyō kanji_ list (e.g. on
[Wikipedia](https://ja.wikipedia.org/wiki/%E5%B8%B8%E7%94%A8%E6%BC%A2%E5%AD%97%E4%B8%80%E8%A6%A7#.E4.BB.98.E8.A1.A8))
contains another piece of information for each _kanji_ : the year (or range of
years) when the character is learned in school:

[![jōyō kanji
list](https://i.stack.imgur.com/rtyqI.png)](https://i.stack.imgur.com/rtyqI.png)

The numbers `1`–`6` indicating the year of primary school and `S` signifying
secondary education.

Now to your question. I think upon seeing a new word, you should look up the
individual _kanji_ and their "grade" (`1`–`6`, `S`) (for example on
<http://jisho.org>) and decide on this basis which of the _kanji_ you should
try to remember. (If some/all of the _kanji_ are not contained in the _jōyō
kanji_ list, you might want to consider moving on.)

(I expect that standard textbooks for second language learners introduce
_kanji_ loosely in this order. The official textbooks in Japan introduce
_kanji_ strictly in this order.)

_Further reading_

  * [_Kyōiku kanji_](https://en.wikipedia.org/wiki/Ky%C5%8Diku_kanji) on Wikipedia
  * [List of _jōyō kanji_](https://en.wikipedia.org/wiki/List_of_j%C5%8Dy%C5%8D_kanji) on Wikipedia

