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Explaining How to Identify Posters in Cases of Defamation on ''


Explaining How to Identify Posters in Cases of Defamation on ''

“” is a website where users can vote either “like” or “dislike” and post comments to share their opinions about celebrities and famous people.

While it is supposed to be a fun community where like-minded people can gather and exchange information, it has become a place for malicious comments and defamation.

In this article, we will explain how to identify the poster if you have been defamed on

What is[jn] is a website operated by the Management Office, where users can openly discuss their opinions about celebrities and famous people. The rankings are divided into the following three categories:

  • “Popularity Ranking”
  • “Unpopularity Ranking”
  • “Trend Ranking”

Under each ranking, there is a “New Comments” section, where the photos of celebrities and the time of the latest comments are displayed in the format of “1 minute ago”, “2 minutes ago”, etc. Therefore, you can see who the latest comments were about.

By clicking on someone’s photo or searching, you can open the page of a celebrity or famous person and view the latest 20 comments. For each comment, you can rate it as “good” or “bad”, indicating agreement or disagreement.

In the comment section, you can choose to:

  • “Show All”
  • “Only Like”
  • “Only Dislike”

It seems that many people choose to “Show All”.

For example, let’s say in the comment section of a favorite comedian A, someone mentions another comedian B, who is similar in age and career, and writes:

“B is much funnier”

Upon finding the above comment, some people respond by citing the response number and saying:

“Don’t act like you know anything about comedy”

Furthermore, some people go to B’s comment section and write:

“You should just retire”

As a result, the comment sections of A and B become a place for mutual insults, and they are filled with defamatory comments.

Even though A and B are not involved, there may be a flame war. Especially for newcomers or young people who have just debuted, it is necessary to delete malicious false comments or exaggerated negative comments as soon as possible to prevent the damage from spreading.

However, simply deleting the comments may not solve the problem. Even if you can delete the offending comment, there is a possibility that the same person will repeatedly post malicious comments or that the article will be reposted on another platform, especially if the comment is clearly intended to harass or has a clear purpose.

In order to prevent the above situation and completely solve the problem, it is necessary to identify the poster and take legal action to pursue responsibility.

Comments that constitute defamation or insult crimes are also posted

If the content of a comment constitutes a defamation crime or an insult crime, it is possible to pursue criminal responsibility against the poster.

Defamation is defined in Article 230 of the Japanese Penal Code as follows:

Anyone who publicly states a fact and defames another person’s reputation, regardless of whether the fact is true or not, shall be punished by imprisonment for up to three years or a fine of up to 500,000 yen.

Japanese Penal Code Article 230, Paragraph 1

For example, comments that indicate specific facts about a certain celebrity, such as “has a criminal record” or “had an affair”, are likely to be subject to defamation.

If no specific facts are indicated, it may be possible to pursue criminal responsibility for insult.

Insult is a crime defined in Article 231 of the Japanese Penal Code. The text of the law is as follows:

Anyone who publicly insults another person, even without stating a fact, shall be punished by detention or a fine.

Japanese Penal Code Article 231

Insulting expressions that do not refer to specific matters, such as “ugly” or “stupid”, may constitute an insult crime.

Identifying the Poster Requires a Request for Disclosure of Sender Information

In order to take legal action against those who post malicious or false comments and hold them accountable, it is necessary to know the name and address of the person in question.

To find out the name and address of the anonymous poster on, a request for disclosure of sender information is made to the administrator (operating company), asking them to disclose the poster’s information.

A request for disclosure of sender information is a request for information disclosure based on Article 4 of the Japanese Provider Liability Limitation Act (official name “Act on the Limitation of Liability for Damages of Specified Telecommunications Service Providers and the Disclosure of Sender Information”, enacted on May 27, 2002 (Heisei 14)).

This is a system that requests the provider, who holds the information (address, name, registered phone number, etc.) of the sender who has defamed others on the Internet, to disclose this information.

First, let’s confirm about the provider.

Two Types of Providers

Anyone using the Internet will first need to contract with a “transit provider” (Internet Service Provider).

A transit provider is a business that connects to the Internet through a line. To connect a line to the Internet, a contract with a transit provider is necessary.

This applies not only to services like fixed lines, but also to mobile phones and smartphones.

Through the transit provider, you connect to sites operated by “Content Service Providers”, in other words, “operators of websites and web services”.

As mentioned above, there are two types of providers: “Content Service Providers” and “Transit Providers”.

Procedure for Identifying Posters on

So, what steps should you take to actually identify the posters on

There are five steps in total.

  1. Identifying the operating company
  2. Requesting disclosure of IP address and timestamp
  3. Prohibition of log deletion
  4. Lawsuit for disclosure of sender information
  5. Claims for damages or criminal complaints

In the following, we will explain these five steps in detail.

Step 1: Identifying the Operating Company through a Bar Association Inquiry

In order to identify the poster, we first make a request for the disclosure of sender information. However, the operating company of the website “” ( is unknown and does not disclose its address, making it impossible to make a request as it stands.

There are several ways to identify an unknown operating company. On “”, advertisements from multiple Japanese companies are posted. The advertising agencies delivering these ads have contracts to post ads on the site, so they have information about the operating company.

In other words, by asking the advertising agency for information about the operating company, there is a possibility that the administrator can be identified. However, advertising agencies usually do not disclose personal information.

This is where a “Bar Association Inquiry” comes in handy. We explain this in detail in the article below.

When an inquiry is received from the Bar Association, there is a very high likelihood of receiving a response.

Once the operating company is identified, it becomes possible to apply for the disclosure of the IP address.

Step 2: Request for Disclosure of IP Address and Timestamp via Provisional Disposition Procedure

When a request for sender information disclosure is made, the operating company of the content service provider,, will determine whether the request meets the legal requirements and decide whether to disclose the information.

While they may voluntarily comply with the disclosure request, the usual response is, “We cannot comply with the disclosure request unless a public judgment is made by the court.” Therefore, you will need to file a provisional disposition for sender information disclosure against

From the provider’s perspective, the person who posted the content is a customer, and from the viewpoint of personal information protection, there are hardly any cases where they comply with voluntary information disclosure requests.

When requesting the disclosure of the IP address and timestamp, a swift procedure called provisional disposition is taken, rather than a formal lawsuit procedure. Although lawsuits inevitably take time, the process of provisional disposition takes about 1 to 2 months.

If the information disclosure is approved by the provisional disposition, must promptly disclose the IP address and timestamp.

What are IP Address and Timestamp?

Since is completely anonymous, the operating company cannot identify the poster’s name or address.

However, there is information that the operator definitely knows. That is the poster’s “IP address and timestamp”.

An “IP address” is the address information on the Internet. All machines connected to the Internet, such as home PCs and smartphones, have their own IP addresses.

When you connect to a site or make a post, the “IP address” of the relevant poster and the “timestamp” of the access time are recorded by the content service provider.

Since administrators usually record the IP address and timestamp, they will be asked to disclose the IP address and timestamp of the person who made the post.

Conditions for Requesting Sender Information Disclosure

When can you request sender information disclosure? The Japanese Provider Liability Limitation Act states:

1. When it is clear that the rights of the person requesting the disclosure have been infringed by the distribution of infringing information. 2. When the sender information is necessary for the exercise of the right to claim damages by the person requesting the disclosure, or when there is a legitimate reason to receive the disclosure of the sender information.

Article 4 of the Japanese Provider Liability Limitation Act

It is only when either of these applies that you can request the disclosure of sender information.

From this provision, the requirements for a sender information disclosure request can be said to be ① the clarity of the rights infringement and ② a legitimate reason to receive the disclosure.

① The clarity of the rights infringement means that in addition to the fact that a person’s rights have been infringed, there are no circumstances that would negate the illegality of the matter. The types of rights infringements claimed include defamation, emotional distress, and privacy infringement, each with different requirements and criteria for establishment.

As for ② the legitimate reason to receive the disclosure, it is generally considered acceptable if “the disclosed information is necessary when claiming damages”.

Step 3: Prohibition of Log Deletion

Once the poster’s IP address is disclosed in Step 2, you can identify the transit provider used by the sender either through the URL or by using a provider identification service such as “WHOIS”.

Next, you will request log information from the transit provider, asking them to disclose the name and address of the person who was connected at this time with this IP address. However, logs, whether from mobile carriers or transit providers, can amount to tens of millions or even millions, respectively, and are therefore scheduled to be deleted after a certain period.

Mobile carriers delete logs after about three months, and fixed-line providers also delete them after about a year. Therefore, if it takes a long time to file a lawsuit from the time of posting, there is a possibility that the logs will disappear.

On the other hand, asking a provider to disclose the sender’s name and other information involves requesting significant personal information, so it is usually done through a regular civil lawsuit. However, it often takes several months to complete the procedures of a regular civil lawsuit.

In order to prevent the logs stored by the provider from being deleted while the procedure is being carried out, in other words, to prevent the evidence from disappearing, it is necessary to take provisional measures to prohibit the deletion of logs.

However, most providers will keep the logs if they are notified that “we are asking for the disclosure of the address and name through the court, so please keep the logs for a while”. Therefore, in many cases, notification alone is sufficient.

Step 4: Lawsuit for Disclosure of Sender Information

Once the preservation of logs is guaranteed, you will initiate a lawsuit for the disclosure of sender information against the intermediary provider, seeking the disclosure of information such as the sender’s address and name.

As a general rule, the intermediary provider will not comply with the disclosure of sender information unless the sender consents.

Since addresses and names are important personal information, the court will only order the disclosure of the address and name through a formal lawsuit procedure if it is deemed illegal.

Step 5: Claim for Damages, etc.

If it is recognized that “rights have been infringed due to the content of the post,” and it is judged that “there is a legitimate reason,” the court will order the provider to disclose the name, address, etc. of the subscriber used at the time of posting.

If the sender is identified by the disclosure of sender information, there are several possible actions that can be taken against the sender. Of course, it is also possible to choose multiple options.

  • Make them pledge not to defame in the future
  • Claim for damages
  • Claim for the expenses incurred in the disclosure process
  • File a criminal complaint

Summary: Consult Lawyers If you’re troubled by defamation on

If you are defamed on the internet, simply removing the offensive post may not fundamentally solve the problem. It is crucial to identify the poster and hold them accountable.

However, the procedure can be quite complex as the operator of is unknown. For early resolution and prevention of recurrence, we recommend consulting with a lawyer who has advanced expertise and extensive experience.

Managing Attorney: Toki Kawase

The Editor in Chief: Managing Attorney: Toki Kawase

An expert in IT-related legal affairs in Japan who established MONOLITH LAW OFFICE and serves as its managing attorney. Formerly an IT engineer, he has been involved in the management of IT companies. Served as legal counsel to more than 100 companies, ranging from top-tier organizations to seed-stage Startups.

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