The Three "Alphabets" of Japanese

Many English-speakers first learning Japanese are at first confused by the writing system for several reasons, from unfamiliarity to plain old misinformation. To help my fellow fans of Japanese out, here's a very generic breakdown of how it all fits together:

There are three writing "alphabets" (quotes because it's not technically correct to say alphabet, but close enough). They are:

Kanji: Literally "Chinese characters", these are adopted and adapted symbols that carry both sound and pictoral meaning. Here's an example: 漢字 (kan-ji). Kanji's pictoral meanings are very useful because even if a beginner doesn't know how to pronounce the two-kanji word 火山, they can still guess the meaning: "fire" + "mountain" = "fire mountain" = "volcano" (which is said "ka-zan" if anyone was curious).

Hiragana: This is a shorthand alphabet showing only the sound. Example: ひらがな (hiragana)

Katakana: This is a second more angular shorthand alphabet, showing only sound as well. カタカナ (katakana)

Kanji can be used for nouns, adjectives, verbs, etc.. Hiragana are most often used for particles and grammar stuff (verbs, verb endings, question marker, and so on). Katakana are used mainly for foreign words and special emphasis.

So, in a single sentence, you can see all three used. For example:

私はアメリカ人です。

This means "I am an American." (Watashi wa Amerikajin desu.) Can you pick out the two kanji, three hiragana, and four katakana? Let's take a look...

Kanji: 私 (watashi - I)、人 (jin- person)

Hiragana: は (written "ha" but here pronounced "wa" as it marks the subject of the sentence, the person or thing doing the action), です (desu - to be)

Katakana: アメリカ (Amerika - America)

As you can see, the two kanji were both nouns, the hiragana served as a grammar particle (wa) and a verb, and the katakana was used to write the foreign name America. 

Children first learn hiragana for everything as it's easiest and then add the right kanji as needed from there.

Well-meaning Japanese will at times write adult foreigners entire letters in hiragana, thinking they're making it easier for you, but in reality, at least in my case, it just drove me insane because it makes it more difficult to tell where one word ends and the other begins. For example, that same sentence above in all hiragana is わたしはあめりかじんです。

If you're just setting out, I'd recommend learning the hiragana and katakana first but getting into kanji as soon as you can. Once you learn the first basic 100, the rest are pretty much just combinations of them and not as insane as they look when you first start. (美, "bi", one of my favorite kanji, means "beautiful" and is just "big" 大 set under a "sheep" 羊).