Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Excellent Reference Source

This is an excellent Kanji dictionary. Not only can you look up characters by either their radical or their reading, the dictionary provides a comprehensive list of compound words in which that character appears. This means that you can often find the meaning of a compound word by looking up only one character (even if you know neither of the character's readings) which saves a lot of time and frustration. The dictionary also includes older versions of characters and characters which have become obsolete (and are not found in most dictionaries). Highly recommended both for students and professional translators of Japanese.