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How to Open a .jtd File (Ichitaro)

A .jtd is a document from Ichitaro (一太郎), the word processor from JustSystems. You do not need Ichitaro itself: the free Ichitaro Viewer for Windows shows and prints it.

.jtd .jtdc .jtt .jttc .jtsd
Open it on this site

Why it will not open

  • Ichitaro is still used in Japanese government offices and schools, and their documents sometimes arrive as .jtd files. Windows and macOS have nothing installed that opens them.
  • The official viewer exists for Windows only. JustSystems' download page offers no Mac, iPhone or Android version.
  • The extension varies: .jtdc is a compressed Ichitaro document and .jtsd a document with an electronic signature. Ichitaro Viewer reads both.

How to open it

Windows: Ichitaro Viewer (free)

  1. 1 Download Ichitaro Viewer from the JustSystems website. The current one is Ichitaro Viewer 2022, version 32.0.3 (updated 19 October 2023, about 39 MB).
  2. 2 JustSystems says it displays documents as Ichitaro 2022 does, and can use Ichitaro's advanced printing (enlarged and reduced, poster, layout, crop-mark and booklet printing).
  3. 3 It runs on the Japanese-language editions of Windows 11 and Windows 10 (Home and Pro), as a 32-bit program on 64-bit Windows.
  4. 4 It also reads Word documents (doc/docx), RTF, plain text and OpenDocument (odt) files.

Mac, iPhone and Android

  1. 1 There is no official viewer. The JTD viewer on this site opens a .jtd in the browser and saves it as Word, PDF or text, without uploading it. It lays the pages out itself, so line breaks can differ from Ichitaro's, and figures and vertical writing are not shown.
  2. 2 Where the layout matters, ask the sender to save the document as a PDF (Ichitaro 2011 and later can) or as a Word .doc file and send it again.

The extensions

.jtd is an Ichitaro document and .jtt a template. .jtdc and .jttc are their compressed versions (Ichitaro 11 and later), and .jtsd is a security document with an electronic signature (Ichitaro 2004 and later). Ichitaro Viewer lists all of these among the files it reads.

When a downloaded .jtd will not save properly

JustSystems notes that some browsers fail to save a .jtd downloaded from a website correctly. The cause is that the web server's MIME settings do not list Ichitaro's extension; the server's administrator can fix it by adding one.

Checking what a file is

The file identifier on this site recognises an Ichitaro document from the streams inside it, even when the extension has been lost or changed.

Formats that turn up in the same situation

Not sure what your file is? Identify it

Frequently Asked Questions

Can Ichitaro Viewer edit the document?
It is for viewing and printing. Editing a .jtd needs Ichitaro itself.
How do I turn a .jtd into a PDF?
Open it in Ichitaro Viewer and print it to Windows' built-in "Microsoft Print to PDF" printer, which saves the pages as a PDF.
Can I read it on my phone?
There is no official viewer for iPhone or Android. The reliable way is to ask the sender for a PDF.