Hakkutsu — Japanese Immersion

Local-first open-source Japanese immersion extension with offline dictionary, Kuromoji parsing, SRS, and dual subtitles.

Hakkutsu (発掘) is an open-source, local-first Japanese immersion toolkit. Read web articles, read raw manga, and watch YouTube or Netflix while looking up unfamiliar vocabulary, mining sentences, and reviewing with spaced repetition—all without leaving the page. KEY FEATURES 1. INSTANT INLINE DICTIONARY & FURIGANA • Hover over or select any Japanese text to view readings, definitions, JLPT levels, pitch accents, and stroke order diagrams. • Clean furigana distribution above kanji characters. • High-quality Japanese audio pronunciation for words and sentences. • Fast offline tokenization powered by Kuromoji and JMDict. 2. INTERACTIVE DUAL SUBTITLES (YOUTUBE & NETFLIX) • Synchronized dual subtitles with interactive Japanese captions. • Hover over subtitle words to pause playback and inspect dictionary definitions in context. • Interactive side-panel transcript: browse dialogues line by line, search spoken words, and jump to any timestamp. • Works across YouTube, Netflix, and compatible HTML5 video players. 3. MANGA & IMAGE OCR • Read raw Japanese manga and comics in your browser. • On-device OCR (Tesseract LSTM) automatically detects dialogue speech bubbles and vertical text. • Click speech bubbles to inspect vocabulary and grammar instantly without typing. 4. 1-CLICK SENTENCE MINING & ANKICONNECT • Save the word, target sentence, source URL, and screenshot to your vocabulary collection in one click. • Direct 1-click export to local Anki via AnkiConnect with custom field mapping (word, reading, audio, definition, sentence, screenshot). 5. BUILT-IN SPACED REPETITION (FSRS) • Review your cards directly in the browser using the modern FSRS-4.5/5 memory model (Difficulty, Stability, Retrievability). • Audio-First Mode: Trains listening comprehension with masked text and auto-played audio. • Cloze Deletion Mode: Fill-in-the-blank context recall. • Smart deck filters by JLPT level (N5–N1), source domain, and due status. 6. 8-LANGUAGE INTERFACE & DEFINITIONS • Supports English, Tiếng Việt (Vietnamese), 日本語 (Japanese), 中文 (Chinese), 한국語 (Korean), Español (Spanish), Français (French), and Bahasa Indonesia (Indonesian). --- PRIVACY FIRST — ZERO REMOTE TRACKING • 100% Local Storage: Mined cards, review history, and settings remain exclusively in your browser's IndexedDB and local storage. • No Account Required: No registration, no ads, no trackers, and no external telemetry servers. • Full Data Ownership: Export or restore your collection anytime via CSV or full JSON backup. --- HOW TO USE 1. Highlight or hover over Japanese text on any webpage to inspect definitions. 2. Open YouTube or Netflix to access dual subtitles and the side-panel transcript. 3. Click the '+' button on any dictionary entry to save it to your SRS deck or export to Anki. 4. Open the extension popup or dashboard to review your due flashcards. Open source under the MIT License.