ReadWrite Kanji — sources and attribution

KANJIDIC2 and JMdict
This application uses KANJIDIC2 and the Japanese/English components of JMdict from the Electronic Dictionary Research and Development Group (EDRDG). Copyright James William Breen and EDRDG. Dictionary data and adaptations are provided under Creative Commons Attribution-ShareAlike 4.0, subject to the EDRDG General Dictionary Licence Statement.
https://www.edrdg.org/edrdg/licence.html
https://www.edrdg.org/wiki/KANJIDIC_Project.html
https://www.edrdg.org/wiki/JMdict-EDICT_Dictionary_Project.html

Modifications: selected frequency ranks 1–1000 plus 240 additional kanji from the supplied Japanese grammar material; arranged into 152 flexible lessons of up to ten kanji; selected Japanese readings, name readings and English meanings; selected one to seven cumulative spelling/reading/sense-compatible vocabulary or phrase examples per character; added separately identified original number and minute-counter examples, plus editorial vocabulary supplements; generated romaji from Japanese source pronunciations; selected beginner readings and integrated grammar additions into the learning order; converted to JSON and allocated audio IDs. Frequency is based on Mainichi Shimbun newspaper analysis by Alexandre Girardi, not a contemporary spoken-frequency ranking. SKIP and other proprietary dictionary search codes are not included in the app's derived course.

KanjiVG
Stroke illustrations: © Ulrich Apel and KanjiVG contributors, licensed under Creative Commons Attribution-ShareAlike 3.0.
https://kanjivg.tagaini.net/
https://creativecommons.org/licenses/by-sa/3.0/
Snapshot: 70a0b7ae0c18ceb5cb358274b029cce0234a43bc
Modifications: sampled SVG cubic curves into normalized polylines; extracted visible components; added stroke-start/end location guidance. For 噌, the 14-stroke Hyougai SVG is used to match the dictionary’s accepted stroke count. The bundled original SVG files retain their notices. Derived stroke data remains CC BY-SA 3.0.

Dictionary and stroke datasets retain their respective licences. No endorsement by the original authors is implied. Full local source documentation, licences and checksums are bundled in Sources. Original SVGs are bundled in KanjiVG. ReadWrite interface and original teaching prose are separate from these data licences.

Audio
User-supplied MP3s are played when installed. Otherwise the app uses labelled Japanese system speech through Apple's AVSpeechSynthesizer. No third-party audio recordings have been copied into the app. Device speech does not certify native pronunciation or pitch accent.

Number teaching references
Original number/composition examples are marked authored-number; minute durations are marked authored-counter. Number pronunciations were checked against the Japan Foundation Marugoto starter vocabulary and counter pronunciation against University of Texas JOSHU. No source audio was copied.
https://marugoto.jpf.go.jp/assets/docs/download/starter_a/MarugotoStarterWordbook_KH.pdf
https://laits.utexas.edu/japanese/joshu/counters/counters_category.php

Editorial vocabulary additions
Two separately identified, attested entries extend examples for characters with sparse kanji-only vocabulary: the engineering term 噛合 and the literary word 犬吠. English definitions and teaching notes are original. The bundled Sources/editorial-supplements.json lists references, pronunciation evidence and usage context for each. These are vocabulary references, not copied articles or recordings. Specialist and literary uses are labelled.

Romaji
Pronunciations use a Hepburn-style ASCII transcription retaining long-vowel spellings. Internal source pronunciations remain available for source audits and Japanese speech synthesis. The transcription implementation and teaching explanations are original.
https://cldr.unicode.org/index/cldr-spec/transliteration-guidelines
https://chamame.ninjal.ac.jp/index_romanise-en.html