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HelpFrequently asked questions

Logging in Using the Email-Based Authentication Method

Registering an email address

What happens if I don't register an email address?

Without authentication by email, you will generally not be able to log in from outside National Diet Library facilities, nor will you be able to request remote photoduplication or any other NDL service via the Internet.
Also, if you lose your password without registering an email address, you will not be able to reset your password yourself and will need to visit the Tokyo Main Library, visit the Kansai-kan, or contact by postal mail, which will take time.

I don't have an email address. What should I do?

If you have not yet registered an email address to your account, the screen for entering your email address will be displayed when you log in. If you plan to use the NDL Search website or the National Diet Library Digital Collections from outside National Diet Library facilities, we recommend that you obtain an email address so that you can receive authentication codes and register the email address to your account. It is convenient to use an email address that you can check at any time, such as on your smartphone.

Login

Can I keep using my eight-digit password?

If you are still using an eight-digit password that was set before May 20, 2025, or an otherwise easy-to-guess password, we recommend changing it to a more complicated one with 12 or more digits.

Do I need to enter an authentication code every time I use the NDL Search or National Diet Library Digital Collections websites?

The NDL Search, Mina Search, and National Diet Library Digital Collections websites allow the use of a single authenticated login (single sign-on) for all three websites.
If you check the Keep Me Logged In checkbox when logging in to one of the above three websites, you will not need to log in again on that device for 60 days. We recommend keeping Keep Me Logged In checked if you use these services frequently. For your own security, however, please uncheck the Keep Me Logged In checkbox if you share a device with others.

Do registered institutional users also need to enter an authentication code?

Registered institutional users need to enter an authentication code when logging in to the NDL Search or National Diet Library Digital Collections websites.
For information on logging as a partner library of the Digitized Contents Transmission Service for Libraries, please refer to the email sent by the National Diet Library on March 17, 2026.

Troubleshooting

I did not receive an authentication code.

If you do not receive an authentication code, please check the following:

  • You can receive emails from the ndl.go.jp domain
  • The email has not been filtered into your spam folder
  • You entered your email address correctly.
    You will not receive an authentication code if the password you entered is incorrect. Please check your password. If you forget your password, you can reset it via NDL Search as long as you know your user ID and registered email address. Please refer to the NDL Search help.

I forgot my user ID.

If you forget your user ID, you can request your user ID be resent via the ID Resend Form (Japanese).
Please check the following before submitting your inquiry regarding your user ID.

  • User ID of the National Diet Library is valid for three years from the date of registration. Each time you use the NDL's services, the validity period will be automatically extended to three years after the date you use them. After three years have passed from either the date of user registration, the last time you entered the NDL (either the Tokyo Main Library or the Kansai-kan), or the last time you logged into NDL web services by entering your User ID and password, your user information will expire.
    If your user registration has expired, it will be necessary to re-register as a new user. Irrespective of whether you apply to be an official registered user or a simple registered user, you may only obtain one User ID. We cannot issue multiple User IDs to one patron. Before registering as a new user, please make sure that you do not already have an existing registration.
  • If you registered via NDL Search, your user ID is included in the email sent to you at the time of registration.
    The subject line of the email is as follows:
    National Diet Library, Japan: Your application for simple user registration has been processed.
    National Diet Library, Japan: Your application for official user registration has been received and you have been granted simple user registration status.

I forgot my password.

If you forget your password, you can reset it via NDL Search as long as you know your user ID and registered email address. Please refer to the NDL Search help.

I'm not receiving the phone call for phone verification.

We only support phone numbers within Japan. We cannot call phone numbers in countries outside Japan.

I want to update my registered email address.

Please select “I did not receive an authentication code or I want to update my registered email address.” in the NDL Search Login Guide and check the information provided there.
If you are able to log in, you can change your email address from “Review or update user information” on the My Account page after logging in.

I entered an authentication code, but I can't log in.

If the user ID or password are incorrect, you cannot log in even if the authentication code you entered is correct. Please check your user ID and password and try logging in again.
If your user ID, password, and authentication code are all correct but you still receive a login error, please select “I enter my user ID, password, and authentication code, but I can't log in.” in the NDL Search Login Guide and check the information provided there.