Getting Japan's online tax filing system e-Tax working

e-Tax is Japan’s online tax filing system. However, like many other pieces of Japanese IT, it can be somewhat difficult to use. The first time I tried logging into e-Tax, I was very frustrated because it seemed like nothing was working. Here’s how you can get e-Tax working.

Table of Contents

• Getting a user identification number

• Software requirements

  • Desktop browser e-Tax version

    • For Windows

    • For Mac

  • Desktop e-Tax software

    • Logging into the web e-Tax version

    • Logging in with My Number card

      • IC Card reader

      • iPhone

      • Android

  • Mobile web e-Tax version

  • Conclusion

Getting a user identification number

Before using e-Tax, you must obtain a user ID, either online or in person at the tax office. You can read about how to do that here. Your user ID is a 16 digital number, separate from your My Number. After that, you need to either use your My Number card to sign procedures, or obtain an electronic certificate from other sources. Some procedures can be signed with a username and password if you go get verified in person at the tax office.

Software requirements

Depends on your operating system, there are different software requirements. It does not seem Linux is supported. Here are the full software requirements.

There’s a few different types of tax software available from the tax agency, such as a dedicated tax return preparation website, as well as different e-Tax versions, such as web, mobile web, and desktop versions. There doesn’t appear to be an e-Tax app. Not all versions support all procedures, such as the web version not supporting appointing a tax administration. You can see which software you should be using on this page under 3. 手続を行うソフト・コーナーを選ぶ (Choose a Software Corner).

Desktop browser e-Tax version

First, you MUST set your browser or system locale to Japanese. Otherwise the web version will fail to load and you will get a screen like this:

This is because the website attempts and fails to load the non-Japanese locale files. You can use the Locale Switcher extension for Chrome and Edge to change your browser locale to Japanese.

When loading e-Tax, you may still get a warning dialog like this about system compatibility, but you may still be able to ignore it. If not, e-Tax will kick you out of the page and you have to resolve your system setup. Click on the link under the 解決方法 (resolution process) column to figure out how to fix the errors.

For Windows

Google Chrome and Microsoft Edge are supported. You need to install this system extension following these installation instructions listed on the software requirements page.

You need to run the extension setup as an administrator, otherwise it won’t let you proceed. When installing the extension, it will ask you if you want to install the JPKI software, but this is only necessary if you want to use the Japanese public certificate authority. You shouldn’t need to install this as it adds extra steps.

There is also a Chrome / Microsoft Edge extension that is optional that will throw a warning check if not installed.

For Mac

Chrome is not supported on Mac, only Safari. I attempted to set my browser agent in Chrome to Safari, however it didn’t work. You need to install this extension listed on the software requirements page, and enable it in the Safari settings page.

It’s okay if your Safari version is outside of the versions listed, it will give you a warning but will still work.

Desktop e-Tax software

e-Tax also has a desktop version that ONLY supports Windows. It is supposed to support the widest range of features. However, I was unable to make it work. e-Tax needs to install additional modules to be able to actually perform various procedures. Even setting my display language to Japanese, and setting the language for non-Unicode languages to Japanese, I was unable to get through the additional modules screen, as all the module names were garbled and I hit an error when I tried to install any of them.

Logging into the web e-Tax version

With the user ID in hand, you can log in. There are two options to log in, either with the username and password that you obtained with the instructions mentioned above, or with your My Number card.

Logging in with My Number card

You can log in by scanning your physical My Number card. One benefit of this method is that you can digitally sign procedures on e-Tax. Technically there are other ways to digitally sign actions on e-Tax, but they are more involved and require obtaining a separate digital certificate.

IC Card reader

You can buy a separate IC card reader to scan your My Number card to login. I don’t have screenshots of this procedure.

iPhone

All iPhones from iPhone 7 and on should be able to read My Number cards. You need the Mynaportal app to scan the QR code given.

Android

I’m not totally sure what Android models support reading My Number cards, likely you need NFC with Felica support, which are mostly found in Androids sold domestically in Japan, but also some foreign Android models.

Similarly to iPhone, you need the Mynaportal app to scan the provided QR code and login.

Mobile web e-Tax version

There’s also a version of e-Tax optimized for mobile web. There’s no app that I know of so far. I haven’t actually used this yet, but there’s various ways to login, from using the user id and password, scanning your My Number card, or logging in through the Mynaportal app.

Conclusion

After logging in, you should be able to do the various procedures. To actually sign, you need either a My Number card or electronic certificate, though apparently you should be able to still use the username and password to file tax returns.

I hope this guide helps people figure out the complexities of getting e-Tax working.

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