Tsundoku, or the pile
The Japanese have a word for the books you buy and do not read yet. It is older than you think.
The editors · 11 October 2026
Tsundoku (積ん読) is the habit of buying books and letting them pile up, unread. The word is a small joke. Tsunde oku means to pile something up and leave it for later. Doku means reading. Put them together and the pile becomes a kind of reading.
It is not new slang. Andrew Gerstle, a professor of pre-modern Japanese texts at SOAS in London, told the BBC in 2018 that the word appears in print as early as 1879, in the Meiji era. It was already a joke about bookish people then. Today you can find it in the Cambridge Dictionary.
A word that does not scold
Most words for unread books are complaints. Backlog. Guilt pile. To-be-read. They make reading sound like work you have fallen behind on. Tsundoku is softer. It describes a habit, and it smiles a little while it does.
That is why we use it in the app. The number on your home screen is not called “To read”. It is called Tsundoku. It is not a debt. It is the part of your library that is still ahead of you.
Waiting since
Every book in the pile has a date: the day it came into the house. Some arrived last week. Some have waited since a move, a birthday, a bookshop in a city you visited once. The oldest one is often the most interesting. Ask yourself why it is still here. There is usually a good reason.