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A Japanese Immersion Toolkit

Understand the Japanese you actually watch.

Content at your level is rarely interesting. Interesting content is rarely at your level. Katarineko helps you bridge that gap. Break down real content line by line, and generate stories at your level that introduce the vocabulary and grammar you need to follow it.

How it works

A simple loop for steady comprehension gains

Import subtitles and video from what you watch. Each step builds on the last.

Step 1

Decode in context

Every line gets readings, word meanings, and grammar roles. Study while watching or reading, without leaving the app.

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Step 2

Retain what matters

Save lines you want to remember. A gentle review system brings them back without the guilt of a growing backlog. Review with high-quality speech synthesis or audio clipped directly from your content.

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Step 3

Bridge into harder content

Generate short stories at your level that introduce the vocabulary and grammar from what you're watching. Each one prepares you to understand a little more.

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Study modes

Two study modes, one learning flow

A video player built for immersion

Watch, align subtitles, inspect lines, and save what matters without leaving the player.

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A reader built for comprehension

Read sentence-by-sentence with analysis visible so you can focus on understanding, not context switching.

Reading mode showing subtitle sentence analysis and path to SRS
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Pricing

The core of Katarineko is free forever. Not a trial, not a freemium tease. Pro only adds story generation.

Free forever

$0

No account needed. No limits.

  • Subtitle import & parsing
  • Word-level analysis with readings
  • Grammar role breakdowns
  • Video player with subtitle sync
  • Reading mode
  • Spaced review with gentle scheduling
  • Export to Anki

Pro

$9.99/mo

or $79.99/yr

  • Everything in Free
  • Generated bridge stories tailored to your level and content
  • Stories you generate are yours to keep, even if you cancel

Built for focused study on Mac

A native macOS app that respects your time and your data.

  • Native SwiftUI — fast, light, no Electron
  • Works offline after initial setup
  • No analytics or ad tracking SDKs
  • Your data stays on your device
  • Clear privacy policy and terms of service