A quiet second pass
The rule-based engine checks committed Japanese for grammar, particles, conjugation, vocabulary, and register issues. It does not run a cloud model or log raw keystrokes.
Correction
Catch Japanese mistakes without sending your writing to the cloud.
Kaku waits until your sentence is complete, checks it locally, and explains the issue in plain English beside the text you are writing.
Mail — Japanese draft
会社を行きます。
Particle
会社に行きます。
会社を行きます。
Use に for the destination of movement with 行きます.
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For everyday Japanese writing
Use Correction while drafting chats, email, documents, and notes. It works best as the safety net that appears after a complete thought—not as another keyboard candidate window.
Correction stays out of the way
Write first. Understand the issue. Decide what changes.
Finish the sentence
Kaku waits for committed Japanese and does not interrupt active IME composition.
Review the explanation
The issue, suggested text, and concise English reason appear beside your cursor.
Apply or dismiss
Accept the focused fix or leave the sentence exactly as you wrote it.
Before and after
A particle fix you can understand
Kaku changes を to に because movement verbs mark the destination with に—and tells you that rule instead of silently replacing the sentence.
Before
会社を行きます。
After
会社に行きます。
Fully on-device
Correction does not send the sentence to Kaku AI. The local engine analyzes committed text in memory and never records raw keystrokes.
Where you already write
Use it in supported chat, mail, document, note, and browser text fields exposed through the operating system accessibility layer.
Install Kaku on your desktop.
Kaku is a lightweight desktop app — not a browser extension. Sign in with Google after install to enable cloud features.
macOSBeta.dmg · Apple Silicon & IntelmacOS 13+
Windows.exe · Windows 10 / 11 · x64Coming soon