Dear Valued Guest,

Thank you for booking your stay with THE AOYAMA GRAND HOTEL.

We regret to inform you that it has come to our attention that an unauthorized third party gained access to an external system used by our hotel for reservation management, and that information relating to your reservation may have been viewed or obtained. We sincerely apologize for the considerable concern and inconvenience this matter may cause you.

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1. Summary of the Incident

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On September 21, 2026, an unauthorized third party accessed “TEMAIRAZU,” the reservation management system used by our hotel and provided by Temairazu Co., Ltd. We are unable to rule out the possibility that some of the reservation information stored in the system was viewed or obtained externally.

Reservations that may be affected:

Reservations made on or before September 21, 2026, with a stay date on or after September 21, 2026.

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2. Information That May Have Been Viewed or Obtained

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Reservation information, including your name, address, telephone number, email address, stay dates, reservation number, accommodation charges, and payment method.

Please note that credit card information is not handled by this system and is therefore not included.

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3. Cause

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The incident was caused by a security vulnerability in a function of a service previously provided by Temairazu Co., Ltd. The company completed corrective measures for the affected component on September 26, 2026, and is continuing its investigation in cooperation with external specialist organizations.

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4. Suspicious Messages Reported

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In connection with this incident, we have confirmed instances of suspicious messages (sent via WhatsApp, email, SMS, and other channels) that impersonate our hotel or booking sites and request that recipients enter credit card information or make payments. Recently, we have also identified emails purporting to relate to “online check-in” or an “accommodation itinerary.”

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5. Our Requests to Guests

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We respectfully ask that you:

 

– Refrain from opening any URLs or links contained in suspicious messages impersonating our hotel or booking sites.

– Refrain from entering credit card information or personal information in response to such messages.

– Refrain from replying to such messages.

– Refrain from making any payment or money transfer as instructed in such messages.

 

We kindly ask that you do not open any URLs or links contained in suspicious emails.

Should you have entered your card information on a suspicious website, please contact your credit card company and financial institution.

 

[Inquiries Regarding the System Involved in This Incident]

Temairazu Co., Ltd. Emergency Help Desk

helpdesk@temairazu.com

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6. Actions Taken by Our Hotel

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– We have requested that Temairazu Co., Ltd. and the other related reservation system providers identify the cause and investigate measures to prevent recurrence.

– We have issued a cautionary notice on our hotel website.

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7. Inquiries

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※Please be aware that, even where the sender’s email address appears to belong to our hotel, it may have been spoofed.

If referring to a single property: Our property's official email address is as follows. If referring to multiple properties sharing one address: Our properties' official email address is as follows. If referring to multiple addresses: Our properties' official email addresses are as follows.

【THE AOYAMA GRAND HOTEL・reception@aoyamagrand.com】

 

[Inquiries to the System Regarding the Incident]

Temairazu Co., Ltd. Emergency Help Desk

helpdesk@temairazu.com

 

Once again, we extend our deepest apologies for the considerable concern and inconvenience this matter has caused.

Sincerely,

THE AOYAMA GRAND HOTEL

Operated by Plan・Do・See Inc.

 
 
 
Dear Valued Guests

Thank you for always choosingAoyama Grand Hotel.

We have recently experienced unauthorized access by a third party to an external system that our hotel uses for reservation management.
It has come to our attention that information regarding your reservation may have been viewed or obtained.

We sincerely apologize for the great concern and inconvenience this has caused.

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1. Overview

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On September 21, 2026, our hotel's reservation management system, "TEMAIRAZU" (provided by Temairazu Co., Ltd.), was subjected to unauthorized access by a third party.

It cannot be ruled out that some of the reservation information stored in the system may have been viewed or obtained from an external source.

Reservations that may be affected:

Reservations made by September 21, 2026, and stays on or after September 21, 2026.

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2. Information that may have been viewed or obtained

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Reservation information including name, address, phone number, email address, accommodation dates, reservation number, accommodation fee, payment method, etc.

This system does not handle or include credit card information.

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3. Cause

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This was caused by security vulnerabilities in some features of services previously provided by Temairazu Co., Ltd.

The company has completed countermeasures for the affected area as of September 26, 2026.

We are continuing our investigation in cooperation with external expert organizations.

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4. Measures to prevent secondary harm

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In connection with this matter, suspicious messages (WhatsApp, email, SMS, etc.) impersonating our hotel or booking site have been sent.
We have confirmed instances where users are asked to enter their credit card information and make payments.

Recently, emails purporting to be “Online Check‑in” or titled “Reservation Details” (or “Reservation Itinerary”) have also been observed.

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5. Requests to Our Guests

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Do not open any suspicious messages, links, or URLs that appear to be from our hotel or from booking sites.

Do not enter your credit card information or personal information in response to suspicious messages impersonating our hotel or booking website.

Do not reply to suspicious messages that impersonate our hotel or booking website.

Do not make any payments or transfers as instructed in the message.

 

[Inquiries regarding this matter]

Temairazu Co., Ltd. — Emergency Help Desk

helpdesk@temairazu.com

 

If you have entered your card information on a suspicious website, please contact your card issuer and financial institution immediately.

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6. The Hotel’s Response

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Requesting that Temairazu Co., Ltd. and related reservation-system providers conduct an investigation to prevent recurrence and identify the cause.

Notice on our hotel website

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7. Contact Us

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*Even if the sender's email address appears to be that of our hotel,

The sender's address may be forged, so please do not open any URLs or links in suspicious emails.

【青山グランドホテル・reception@aoyamagrand.com】

 

[Inquiries regarding the system that caused this issue]

Temairazu Co., Ltd. — Emergency Help Desk

helpdesk@temairazu.com

 

Once again, we sincerely apologize for the great concern and inconvenience caused.

I sincerely apologize.

 

About Aoyama Grand Hotel

Operated by: Plan・Do・See Co., Ltd.