A fascinating essay by Shoko Mugikura on the complexity of Japanese writing.
Modern Japanese is written in a mixture of three basic scripts: Kanji — which are Chinese ideographic symbols — as well as Hiragana and Katakana — two phonetic alphabets (syllables). There are a few thousand Kanji characters, while Hiragana and Katakana have 46 each. Although there is a basic rule for when to use which script, there are many exceptions, and what’s worse is that words written in Kanji have often multiple pronunciations, depending on the context or conjunction. This is hard enough for native speaker to get right every time, so I almost feel sorry for those non-natives who are learning to read and write Japanese.
Here's a quick breakdown of the three basic scripts and their usage:
Kanji is mainly used for the lexical elements: nouns, verb stems, adjective stems, and so forth; Hiragana has rounded letter shapes, which are mainly used for the grammatical elements of sentences such as particles, auxiliary verbs, and suffixes of nouns; Katakana has an angular letter shape, which is most often used for foreign words and also for the purpose of emphasis.