
Eiji Akutsu is a newspaper reporter. He is working on unsolved case that took place 30 years ago. The case involved a group of people extorting several companies for money. The group sent cassette tapes to the companies. Eiji Akutsu comes across a mysterious cassette tape. Meanwhile, Toshiya Sone lives in Kyoto and runs a tailor shop. He discovers a cassette tape among his late father's possessions. He plays the cassette tape and hears his voice from his childhood days.
Sumi no Koe is a Japanese movie of 566 characters, with 138 unique words and 83 different kanji. Its difficulty rating on Jiten is hard, 3.5 out of 5. The full vocabulary list ranks all 138 words by how often they appear, and you can study them on Jiten or download them as an Anki deck.
This title is too short to reliably find similar media.
Here are some of the words that appear most often in this media, as well as a sample of its rarer vocabulary.