Credits & Attribution
RT Nihongo Club is built on the shoulders of open data projects that make Japanese language learning accessible to everyone. Everything below names the project, its license, and exactly what we changed. The full notice texts are in our third-party notices.
JMdict (via jmdict-simplified)
Our vocabulary database is powered by JMdict, the comprehensive Japanese–English dictionary maintained by the Electronic Dictionary Research and Development Group. Every entry in our dictionary keeps its JMdict sequence number, and word-frequency ordering derives from JMdict’s own priority data.
- Author / holder:
- Electronic Dictionary Research and Development Group (EDRDG)
- License:
- CC BY-SA 4.0
- Our changes:
- Content filter: 38 entries excluded and 137 senses removed (documented in data/README.md) Romaji, JLPT levels, frequency ranks and learn ordering are our own additions
This publication has included material from the JMdict (EDICT, etc.) dictionary files in accordance with the licence provisions of the Electronic Dictionaries Research Group.
Our adaptations of this data are available under the same license: if you want the JMdict (via jmdict-simplified) portions of our database in their adapted form, contact us and we will provide them under CC BY-SA 4.0.
Japanese Wiktionary (via wiktextract)
Japanese-language definitions and etymological notes (the 日本語 definition panels) come from Japanese Wiktionary, extracted with the wiktextract tool by Tatu Ylonen. Each panel links back to the source page it came from.
- Author / holder:
- Wiktionary contributors; extraction tool © Tatu Ylonen (MIT)
- Source:
- ja.wiktionary.org
- Our changes:
- Filtered to lang_code === "ja" entries, readings normalized, redirects dropped, reshaped into our sense schema
Academic use of the extracted data should cite: Tatu Ylonen, "Wiktextract: Wiktionary as Machine-Readable Structured Data", Proceedings of LREC 2022, pp. 1317–1325, Marseille.
Our adaptations of this data are available under the same license: if you want the Japanese Wiktionary (via wiktextract) portions of our database in their adapted form, contact us and we will provide them under CC BY-SA 4.0.
KANJIDIC2 (via kanjiapi.dev)
On and kun readings for our 2,136 kanji come from the KANJIDIC2 project, accessed via the kanjiapi.dev API.
- Author / holder:
- Electronic Dictionary Research and Development Group (EDRDG)
- Source:
- kanjiapi.dev
- License:
- CC BY-SA 4.0
This publication has included material from the KANJIDIC dictionary files in accordance with the licence provisions of the Electronic Dictionaries Research Group.
Our adaptations of this data are available under the same license: if you want the KANJIDIC2 (via kanjiapi.dev) portions of our database in their adapted form, contact us and we will provide them under CC BY-SA 4.0.
KanjiVG
Stroke-order diagrams and writing practice for kanji and kana are drawn from KanjiVG stroke data by Ulrich Apel.
- Author / holder:
- Ulrich Apel
- Source:
- kanjivg.tagaini.net
- License:
- CC BY-SA 3.0
- Our changes:
- XML prologue, DOCTYPE and per-file copyright comment stripped from each SVG on import; the kvg: element structure is kept intact
Our adaptations of this data are available under the same license: if you want the KanjiVG portions of our database in their adapted form, contact us and we will provide them under CC BY-SA 3.0.
jlpt-kanji-dictionary
The kanji character set, stroke counts, English descriptions, and JLPT level assignments originate from the jlpt-kanji-dictionary project by Egor Kiselev.
- Author / holder:
- Egor Kiselev (AnchorI)
- License:
- MIT
- Our changes:
- 5 descriptions blanked by our content filter
JLPT vocabulary lists
JLPT level assignments for vocabulary come from the JLPT resource lists compiled by Jonathan Waller at tanos.co.uk, which have levelled study vocabulary for learners since the test changed format in 2010.
- Author / holder:
- Jonathan Waller (tanos.co.uk), via jamsinclair/open-anki-jlpt-decks (MIT)
- Source:
- www.tanos.co.uk/jlpt
- Our changes:
- Cross-level duplicates deduplicated (easiest level wins); okurigana headword spellings corrected
Aozora Bunko (青空文庫)
The reading library in Materials is built from Aozora Bunko, the digital archive of Japanese literature whose copyrights have expired. We import only works flagged public-domain in the official catalog, keep the original author and title attribution, and link every work back to its Aozora page.
- Author / holder:
- Aozora Bunko and the original authors
- Source:
- www.aozora.gr.jp
- Our changes:
- Sentence-segmented for the reader; ruby markup normalized
kuromoji.js + mecab-ipadic dictionary
Furigana and word-boundary analysis use the kuromoji.js morphological analyzer by Takuya Asano, which bundles the mecab-ipadic dictionary from the Nara Institute of Science and Technology. The full NAIST notice is reproduced in our third-party notices.
- Author / holder:
- Takuya Asano (kuromoji.js); Nara Institute of Science and Technology (IPADIC)
Text-to-speech (Google Cloud TTS, OpenAI)
All audio on the site is speech synthesized from our own sentences using Google Cloud Text-to-Speech (and OpenAI for some voices). No recorded human speech is used.
- Author / holder:
- Google LLC / OpenAI
RT Nihongo Club original content
Everything else — the example sentences, grammar explanations, kana guide, word relations, chapter curricula, and all teaching notes — was written for RT Nihongo Club and is our own work.
- Author / holder:
- RT Nihongo Club
- Source:
- /credits
- License:
- All rights reserved
Our commitment
- Every license obligation above is checked by an automated gate in our build: a data source cannot ship without its attribution.
- Where we modified open data, the change is disclosed on this page.
- Content is filtered for classroom appropriateness; those removals are documented per source.
Questions about data usage or licensing? Contact us and we will answer within a few days.