Content & attribution

Original learning content

The explanations, exercises and example sentences were authored for Yabai Sensei and checked against language references. They have not been reviewed by a native speaker. No textbook lessons or JLPT examination questions were copied.

Japanese references

Readings and meanings are checked against dictionary references including EDRDG’s JMdict. The vocabulary and kanji word data, and dictionary review report, are available under CC BY-SA 4.0, with acknowledgment to the Electronic Dictionary Research and Development Group. Original selection and simplified definitions were checked using JMdict. Data attribution and reuse terms. Grammar references include The Japan Foundation’s Irodori; its prose and recordings are not reproduced. Kana reference: Tofugu hiragana guide and katakana guide. Reference websites are not sponsors.

Download the N5 vocabulary and kanji word data (CC BY-SA 4.0). WaniKani content, accounts and API data are not used in this curriculum.

Listening audio

Generated using Open JTalk / pyopenjtalk with HTS Voice “Mei,” released by the MMDAgent Project Team, copyright 2009–2013 Nagoya Institute of Technology, Department of Computer Science. Voice model licensed under Creative Commons Attribution 3.0. These are generated recordings of original sentences, not human performances. Full voice license.

Review scheduling

Independent implementation of the SM-2 algorithm described by Piotr Woźniak. Yabai Sensei maps deterministic correct/incorrect answers to quality scores 4/1, uses UTC review instants, and prevents repeated early practice from inflating review intervals.

Visuals and software

Sensei’s cat character was generated specifically for this project. The application uses system fonts and Lucide icons (ISC license). React, Next.js and other dependencies retain their respective open-source licenses.