Data sources

Tatoeba

CC BY 2.0 FR (some CC0)

Community sentences; includes Tanaka Corpus public domain data.

Japanese Wikipedia + Wikinews dumps

CC BY-SA 4.0 + GFDL (Wikinews CC BY 2.5)

Real-world encyclopedic and news-style prose.

Aozora Bunko

Public domain works with attribution rules

Literary sentences and classic prose.

JMdict / EDRDG

CC BY-SA 4.0 (EDRDG license terms)

Dictionary definitions, readings, parts of speech with share-alike.

JmdictFurigana

CC BY-SA 4.0 (built on JMdict)

Which kana belong to which kanji, so furigana sits over each kanji of a word.

KanjiVG

CC BY-SA 3.0 — Ulrich Apel

Stroke order of each kanji, drawn in the word panel.

Japanese WordNet

WordNet-style open license

Synonyms and Japanese definitions for question generation.

Tango Japanese Vocabulary

MIT — Copyright (c) 2026 Oliver Seifert

Licensed beginner examples and translations indexed from a pinned local Anki package.