When is Kanji used versus Kana
 

I've been trying to understand something. When is the kanji used. I've read for Noun for sure. Adjectives and verbs use what is called "okurigana" were the root word is kanji and the extend is in kana. So why is it that the word for dictionary じびき (kana) 字引 (kanji) in the book that I'm studying use the kana and not the kanji? Isn't dictionary a noun? Can someone clarify this for me? Is there no set rule? Thanks.

字引 is indeed written in Kanji, the reason why your book might not write it as kanji may be due to its level. I'm not sure what book you are readying but if it is for learning Japanese, then the book might not use kanji where those characters have not been learnt yet. if it is a children's book, the same reasons.

As anrakushi pointed out, the book in which you saw the word じびき in hiragana may be for children or beginning learners of Japanese. If you look at the textbooks for the 1st-graders in Japan, you will not find too many kanji used.

You asked if there are no set rule. That is not easy to answer because there are at least no 'written rules'. It's only that if a kid refuses to learn kanji in school, he will surely make poor grades. If he still refuses to learn too many of them by the time he reaches his adulthood, he simply won't be able to read newspapers, magazines, legal papers, websites, etc. He won't be functioning as a good citizen. In reality, however, not many people want to be in that kind of a situation; therefore, kids will start learning seriously sooner or later.

So unlike in other countries, the Japanese people write the same sentences or even words differently according to their kanji knowledge. Let me give you an example.

Consider the following sentence and how it's written in Japanese by different age groups. Note that the ages are only approximate:

"I went to the library with John yesterday."

6-year-olds :　わたしはきのうジョンさんととしょかんへいきまし� �。　(no kanji)

7-year-olds: わたしはきのうジョンさんととしょかんへ行きました。　

8-year-olds: 私はきのうジョンさんととしょかんへ行きました。

10-year-olds: 私は昨日ジョンさんととしょかんへ行きました。

12-year-olds: 私は昨日ジョンさんと図書館へ行きました。

With this particular simple sentence, there's no more word that you can write in kanji. So it doesn't matter if you are 12 or 50. The sentence 「私は昨日ジョンさんと図書館へ行きました。」 is the goal for us.

Had the sentence been longer and it contained words that are written using more difficult kanji, then there would have been more steps before reaching the 'final sentence' that looks good to adults (society in general).

Yes you all are right. Now I understand. The book I'm studying is A Japanese Reader by Roy Andrew Miller. It takes you from beginning to advanced. What you said didn't even cross my mind. How stupid of me! Thanks for your insights.

That's interesting. In my dictionary [Oxford Beginner's Japanese Dictionary], it is read as 辞書 (Jishou). What does this mean? Is this not the correct word for dictionary?

there are more than one way to say dictionary in japanese, off the top of my head:
字典、辞典、辞書、字引 also there is 事典 but this is used for encyclopedia

But in what context would you use those, plus the definition I have? That's my main gripe with the Japanese language. There are a lot of readings for certain words, but no real example as to when we would use it or when we should use it. It's very confusing.

this is not a problem with just Japanese, it is a problem with all languages, i can assure you as someone who has spent a lot of time teaching english to students in melbourne that these same problems exist for learners of english.

im used to using either 辞典 or 辞書 for just saying dictionary. there are these examples for when you are referring to more specific things.
電子辞書　でんしじしょ　electronic dictionary
英和辞典　えいわじてん　English-Japanese dictionary
漢和辞典　かんわじてん　Chinese-Japanese character dictionary

also i believe 字典 - this is more of a character dictionary. i'm sure nagoyankee or MMM can come along and shed some light on when to use each one, but my guess is that they are interchangeable except for the above examples.

In Japanese, the word 字典 is seldom used. In fact, many teachers would tell you NOT to use it, but to use 辞典. 　The word 字典 does exist, but only kanji/old Chinese literature scholars use a 字典 to study the words that most people don't even know exist.　So an average Japanese guy like me has never even seen an 字典 in real life. I'm pretty sure those aren't sold in 'regular' bookstores.

If you ever see a japanese use the word 字典, it would most likely be as a mistake.

i have never seen it used and would never use it myself. it is however a synonym for 辞典／辞書 etc and that is why i listed it.