Gyokan

Select text, get a Japanese explanation on the spot.

Select text on any webpage and a Japanese explanation opens right there. Gyokan is a Chrome extension for Japanese-speaking learners of foreign languages, built so you can check translation, grammar, and vocabulary together without breaking your reading flow. The source language is detected automatically (currently tested mainly with English).

Get it on the Chrome Web Store

You'll need an Anthropic or OpenAI API key to use it (choose your provider on the options page). Each explanation you generate and each question it answers is billed to your own account. Text-to-speech relies on your OS's speech engine; depending on your setup, you may need to configure voices in the OS first (on Linux in particular, it may stay silent until you do).

Screenshot of the close-reading explanation panel — **Close reading** — Explains the full translation, key grammar points, and expressions worth learning for the text you selected, right on the page. If something in the explanation is unclear, ask a follow-up question in the box at the bottom of the panel.

Screenshot of a word card — **Word cards** — Click a word in the explanation to see its meaning, phonetic transcription, etymology, and example sentences. Generating another example is one click away.

Screenshot of a phrase card — **Phrase cards** — For phrasal verbs and idioms, it digs into the literal meaning and how that meaning came about.

Screenshot of writing feedback — **Writing feedback** — Write a sentence using the words you looked up, and get a four-level rating with corrections.

Privacy

There is no developer-run server. The text you select and the questions you ask about an explanation are sent directly to whichever provider (Anthropic or OpenAI) you configured with your API key. Your API key, history (including questions and answers), and settings are stored only on your device and are never sent to anyone else, including the developer. See the Privacy policy (Japanese) for details.