Case, Investigation, Culprit: the 10 Words Behind Every Japanese Crime Drama
Published 2026-07-31
Crime and mystery is the biggest genre in our corpus by a huge margin — 34,585 lines of dialogue, more than the next three genres combined. And its vocabulary is wonderfully predictable: every case needs a 事件 (case), a 捜査 (investigation), and eventually a 犯人 (culprit).
Here is the full top 10 — procedural vocabulary so consistent that after one season of any detective show you will know it by heart. Bonus: half of it doubles as news-broadcast Japanese.
Where do these rankings come from?
Word frequency is counted across 34,585 subtitle lines classified into this genre from JESC, an open research corpus of 2.8 million Japanese TV & film subtitle lines (Pryzant et al. 2018, CC BY-SA 4.0).
The map only lists words that already have a reviewed entry in our library — a frequent word you expect may still be in production, and each new set extends the map.
A few entries are compound words counted under their core component (a student-council compound under its base word, for example), so a count can occasionally sit slightly above the entry ranked before it.
Counts tied to specific franchise titles are excluded or adjusted, and the corpus predates 2018 — so the newest slang of a genre can rank lower than it feels like it should.
Word frequency statistics derived from JESC (Japanese-English Subtitle Corpus, Pryzant et al. 2018, CC BY-SA 4.0). No corpus text is reproduced.
The top 10, one by one
incident / case (crime, affair) · 6,376× in this dialogue set
The word every episode opens with. Broader than English “crime” — any incident or affair can be a 事件 — and TV news uses it exactly the same way.
criminal investigation (捜査する = to investigate) · 5,310× in this dialogue set
The police investigation itself. N1 on paper; in this genre it is wallpaper — 捜査する (to investigate) and 捜査本部 (investigation HQ) carry whole episodes.
murder / homicide · 4,468× in this dialogue set
Murder — 殺人事件 (murder case) is practically one word in this genre. Grim, frequent, and unavoidable in both dramas and news.
culprit / offender · 4,401× in this dialogue set
The culprit — the person the whole story is looking for. The reveal line 犯人はお前だ (“the culprit is you”) is the genre's signature move.
evidence / proof · 3,515× in this dialogue set
Evidence. 証拠はあるのか? (“Do you have proof?”) is the standard pushback in every interrogation scene — and a genuinely useful word in real arguments too.
police detective · 2,909× in this dialogue set
The police detective — the genre's protagonist job. Note it is a different word from 警察, the police as an institution.
an arrest (逮捕する = to arrest) · 2,730× in this dialogue set
The arrest that closes the episode. 逮捕する = to arrest; on the news you will hear the passive 逮捕された (“was arrested”) daily.
lawyer / attorney · 2,259× in this dialogue set
Lawyer — the courtroom half of the genre, and one of the profession words learners meet on screen long before any textbook chapter.
suspect (in a crime) · 1,207× in this dialogue set
The suspect — literally “person under suspicion”. News Japanese attaches it to names as a title, the way English says “the suspect”.
trial (in court) · 1,281× in this dialogue set
The trial. 裁判所 (court) and 裁判官 (judge) build on it — courtroom dramas are a vocabulary set of their own.
Why this genre is a stealth news course
The procedural core — 事件, 捜査, 逮捕, 容疑者 — is exactly the vocabulary of Japanese news broadcasts. If you ever want to follow the news in Japanese, a detective season is surprisingly good homework.
Open the Crime & Mystery track — every word with audio and spaced review