SYLLABARIES
Hiragana, katakana and kanji
Japanese uses three syllabaries: hiragana, katakana and kanji. It is important to study them all, because this is the only way you will ever be able to read Japanese.
Hiragana are used to write common words. Technically speaking, you could write Japanese using only hiragana. However, this is not how it works! There are 46 hiragana accounting for the 46 syllables in Japanese.
Katakana are used to write words coming from other languages, such as anglicisms. Words like 'sukaato' (skirt), 'skii' (ski), 'appuru' (apple), etc, will be written using katakana. There are 46 katakana.
Kanji are Chinese unsimplified characters. One kanji can have multiple pronunciations and there are many of them around, although you need at least 2000 kanji to be able to get around in Japan and read Japanese books and newspapers.
HIRAGANA
ひらがな
Hiragana is a Japanese syllabary, part of the writing system along with katakana and kanji. Hiragana were first developed in the 5th century to replace man'yougana, Chinese characters used for pronunciation. At first, hiragana were not accepted by everyone, men preferring to use kanji whereas women of the court started to adopt hiragana.
Today, hiragana are used along with katakana and kanji in Japanese scripts.
KATAKANA
カタカナ
Katakana, unlike hiragana, are used to write foreign words. Japanese has borrowed some words from English, such as 'sukaato' (skirt), and these words are written using katakana. Katakana will also be used to write onomatopoeia and other slang.
Today, a lot of people take creativity using katakana, especially in manga.