Hodoku — Japanese Sentence Breakdown

Highlight any Japanese text to see it in romaji, with a word-by-word breakdown, readings, and the meaning.

Reading Japanese gets a lot easier when you can see how a sentence is built. Highlight any Japanese text on any page and Hodoku shows you: • The whole sentence in romaji, using proper Hepburn spelling — tōkyō, not toukyou • The kana reading, with furigana above each kanji • A word-by-word breakdown: dictionary form, part of speech, how the word is inflected, and what it means • Plain-English notes on particles and auxiliaries — what は, を, に, and ます are actually doing • A save button, so anything worth revisiting goes onto a review list It works entirely offline. The Japanese dictionary and the morphological analyser are bundled with the extension, so there is no account, no sign-up, and nothing is sent anywhere while you read. HOW IT WORKS Select some Japanese and a small "Romaji" button appears. Click it, or press Alt+R, or right-click and choose "Show romaji and breakdown". You can also turn on automatic mode so the panel opens as soon as you finish selecting. ROMAJI THE WAY YOU WANT IT Four styles, switchable in the options: • Modified Hepburn — tōkyō (what dictionaries and road signs use) • Doubled vowels — tookyoo • No long vowels — tokyo • Keyboard spelling — toukyou (what you type on a Japanese IME) Long vowels are resolved from how a word is actually pronounced, not from how it is spelled — so 王 comes out as "ō" while 追う correctly stays "ou". ACCURATE WORD SPLITTING Japanese does not put spaces between words, so a good breakdown depends on good segmentation. This extension uses kuromoji with the IPADIC dictionary — the same morphological analysis approach used by professional Japanese text tools — to find word boundaries, readings, and inflections. Meanings come from JMdict, the standard open Japanese-English dictionary, with over 200,000 entries. OPTIONAL AI TRANSLATION If you want a fluent, natural translation of the whole sentence, you can add your own API key in the options — either Anthropic (Claude) or OpenAI (GPT), whichever you already have. This is off by default and completely optional: romaji, readings, and word meanings all work without it. Translations are cached locally, so re-reading the same sentence never costs a second API call — and a Regenerate button lets you ask again, or ask the other provider, whenever an answer is not quite right. The extension only asks for network permission if you turn this on, it only asks for the provider you picked, and your key is stored in your own browser and sent only to that provider. SAVE WHAT YOU WANT TO REMEMBER Click the bookmark on any sentence to save it. The review page collects everything you have saved, with search and a flashcard study mode. When you are ready to study properly, send them straight into Anki. With the AnkiConnect add-on installed, saved sentences become real Anki cards in a deck you choose — with furigana above the kanji on the answer side — so you get proper spaced repetition and Anki's own sync to your phone. This runs entirely over your own computer's loopback; nothing goes to the internet. You can also export tab-separated or JSON files. FOR LEARNERS Built for anyone reading Japanese above their level: news articles, blog posts, game text, Twitter, novels. If you are working through kanji study and keep hitting words you can nearly read, this fills in the gap without making you leave the page. NO ACCOUNT, NO TRACKING There is no sign-up, no analytics, and no telemetry. The extension requests no network access at all when you install it — the only hosts it can ever reach are the ones you explicitly turn on, and it asks for those at the moment you enable them. OPEN SOURCE MIT licensed. The source, the build scripts, and the pipeline that compiles the dictionary are all public, so you can read exactly what it does with the text you highlight — or build it yourself: https://github.com/randalvance/hodoku