Reading in Japanese

There are 4 systems of writing in Japanese that are used on a daily basis; Kanji, hiragana, katakana, romaji.

Romaji is the use of the alphanumeric characters used in English to represent Japanese sounds. These can often be seen in places where there will be lots of foreigners so that they can also read the signs ect.
This can be seen on the signs in the train station signs:

Here you can see the kanji at the top followed by the hiragana reading and under the green like the romaji.
It is also sometimes used for emphasis to make things look 'cool' and 'edgy' for example in magazines.

Katakana is used mainly for foreign loan words. These are words that come from other languages but have been adopted into the Japanese language for example chicken in Japanese is チキン (chikin). You see these a lot on non-japanese food menus like McDonalds.

Hiragana is probably the most used written system in Japanese. It can be used for as part of a word, in a mix with kanji to make a new word, to show the reading of a kanji and also as the particles that make up a sentence. Hiragana came into use because when the Japanese started to develop a written system using the Chinese Kanji they found that a lot of things would not fit with the Japanese speech patterns such as the lack of particles in Chinese and so hiragana was created.

Kanji is a system of writing borrowed from the Chinese. It is estimated that there are around 50 000 kanji in the Japanese language however it is not necessary to learn them all in order to be classed as fluent. Each kanji has a meaning and different readings dependent on the context is is being used in.
For example あの人はきれいです。(ano hito wa kirei desu.) That person is pretty.
あの人形はきれいです。(ano ningyou wa kirei desu.) That doll is pretty.
They both still mean person but adding the second kanji turns the reading from hito to nin and the meaning to more of a feeling of the form of a person or a doll.