kidoku surū

noun · from 既読 (“read”) + スルー (from English “through”)

Being left on read — but as a named social offense. Two characters on a screen, 既読, created a new way to hurt someone.

2010s

Provenance — where it came from

The messaging app LINE, which spread through Japan in the early 2010s, shows the sender a small mark — 既読 (kidoku), “read” — the moment a message is opened. The feature is said to have been designed with disasters in mind: even if someone cannot reply, you know they saw your message. They are alive.

In daily life, the mark became a clock. The moment 既読 appears, the sender knows you know — and the silence after it starts to mean something. Japanese named this event: 既読スルー (kidoku surū). The second half is スルー, from English “through,” long used in Japanese slang for letting something pass by. Reading and not replying — “read-through.”

The word made a private non-event into a public category, something friends could accuse each other of. It soon needed a sibling: 未読スルー (midoku surū), leaving messages unread on purpose — the art of not opening them at all, so the clock never starts. Two words for two kinds of silence. A safety feature, built to confirm the living, ended up measuring the temperature of friendships to the minute.

Field notes — how it’s used

3日も既読スルーされてる

mikka mo kidoku surū sareteru

“I’ve been left on read for three days.” The mark said “read.” The silence said the rest.

Nearby exhibits

聖地巡礼 seichi junrei “Pilgrimage to sacred sites” — except the sacred sites are the real-world locations of anime scenes. The devotion is not entirely a joke. ガラケー garakē Japan’s flip phones were only given their name — “Galapagos phone” — after the smartphone arrived to replace them. Some things get named at their funeral. 草 kusa It means LOL. The reason involves grass growing across your screen.