Nijuushi no Hitomi is a Japanese novel of 103,015 characters, with 6,375 unique words and 1,320 different kanji. Its difficulty rating on Jiten is expert, 4.0 out of 5. The full vocabulary list ranks all 6,375 words by how often they appear, and you can study them on Jiten or download them as an Anki deck.
Here are some of the words that appear most often in this media, as well as a sample of its rarer vocabulary.