Koi no Aite wa Gouin Joushi is a Japanese novel of 111,991 characters, with 5,269 unique words and 1,272 different kanji. Its difficulty rating on Jiten is average, 2.3 out of 5. The full vocabulary list ranks all 5,269 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.