Japanese knitting symbols
The beauty of Japanese knitting symbols is that they are standardized across publications according to the JIS (Japanese Industrial Standards Association) so this is really a useful reference if you are trying to decipher a Japanese pattern (thanks Yukie for pointing this out). And don't forget that ABCs of Knitting has a wealth of information for both Japanese and English speaking knitters trying to understand each other's ways of charting knitting patterns.
Clear and Simple Knitting Symbols
ISBN 452902413X / 9784529024136
The book covers 120 knitting symbols. This is a lot more than we are used to seeing in English knitting books. We are talking symbols, not actual patterns, and I think this is beacause Japanese knitting books don't give text-only instructions like some western books do, so more symbols are needed to avoid lengthy descriptions. Once you have a way to read the symbols, this really makes better sense.