To Our Valued Customers

Thank you very much for using our website and for your continued support.

Studio Inc. has publicly announced an unauthorized third-party access incident. We used their website creation service, "Studio," to build and host our websites.

[Notice Regarding Unauthorized Access (Studio Inc.)]

We sincerely apologize for the serious inconvenience and concern this incident has caused to our customers and stakeholders.

Below is our report on the confirmed facts and our response going forward.

1. Background of the Incident
On October 16, 2026 (JST), Studio Inc. notified us of unauthorized third-party access to their cloud environment.

According to Studio Inc., a third party exploited a vulnerability in certain CMS features. This allowed external parties to extract data from their cloud environment. Studio Inc. confirmed unauthorized access between September 30 and October 1, 2026 (JST). The data exposure remained active until Studio Inc. resolved the issue on October 14, 2026.

Studio Inc. announced that they patched the CMS vulnerability between October 13 and October 14, 2026. They also completed measures to close the pathways used for the unauthorized access.

2. Information Potentially Compromised
Affected Websites

YAMAGATA Corporate Website: https://yamagata-corp.jp/

Human Resources Services Division Website: https://recruit-now.tokyo/
*Note: The Human Resources Services Division website experienced unauthorized access, but there is no risk of data leakage.

Affected Period
Customers who submitted inquiries via the "Inquiries & Consultations" form on our corporate website between February 21, 2025, and October 14, 2026.

Affected Records
Up to [1,463] submissions

Data Items Involved
Company name, full name, email address, phone number, department name, address, and inquiry details

3. Requests to Our Customers
To prevent secondary damage, please exercise caution regarding the following:

If you receive suspicious or unfamiliar emails, do not open them. Please do not run any attached files or click links inside the email body.

4. Reporting to Authorities
Studio Inc. requested that we withhold reporting this incident to the Personal Information Protection Commission (PPC). We will file the report as soon as we receive further instructions from them.

5. Contact Desk for This Incident
If you have any questions or concerns regarding this matter, please contact our dedicated desk below:

YAMAGATA Corporation

We reiterate our deepest apologies for the great inconvenience and anxiety this situation has caused.

October 19, 2026
YAMAGATA Corporation