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Methods to Identify Anonymous Posters on the Shitaraba Bulletin Board


Methods to Identify Anonymous Posters on the Shitaraba Bulletin Board

Shitaraba Bulletin Board, a famous internet forum on par with 2channel, allows anyone to create bulletin boards of various genres for free. While beneficial information are posted, there are also posts that contain baseless rumors and defamation.

In this article, we will explain how to identify the poster if you have been subjected to defamation or slander due to unfounded rumors, in order to recover from the damage.

What is Shitaraba Bulletin Board?

The Shitaraba Bulletin Board is a rental bulletin board established by Hiroyuki Nishimura, the founder of 2channel. After several changes in management companies, it has been operated by Aegate Corporation since 2018 (Heisei 30).

The Shitaraba Bulletin Board is popular due to its user-friendly interface and wide range of topics. Furthermore, it is free to use, attracting a large number of users.

Like 2channel, it is characterized by its high level of anonymity. It adopts a thread float format where threads with the latest posts are displayed at the top.

Examples of Defamation on Shitaraba Bulletin Board

Due to its high level of anonymity and large user base, the Shitaraba bulletin board often sees issues between posters, defamation towards others, and baseless rumors. Here are some examples:

  • The CEO of XX is connected to the Yakuza
  • XX is a criminal, not fit for society
  • XX is a habitual marijuana user

All of these posts, if left unchecked, can spread harmful rumors that can cause mental distress and disrupt social life. Prompt action should be taken against such malicious content.

How to Request a Deletion

If you simply want to stop the current damage from defamation or slander by deleting the relevant post, you can request a deletion based on the terms of use of the Shitaraba bulletin board.

Procedures for Identifying Posters

①Request for IP Address Disclosure

In Japan, under the Japanese Provider Liability Limitation Act, those who have had their rights infringed upon by illegal posts on the internet are allowed to request the disclosure of information about the person who made the illegal post.

A request for the disclosure of sender information will be made based on the Provider Liability Act to the administrator of the Shitaraba bulletin board in order to identify the IP address used when the relevant post was written.

In principle, a court procedure is required to request the disclosure of an IP address. This court procedure is not a trial, but a provisional disposition, which is a quick procedure. Trials can take a lot of time, but provisional dispositions can be implemented in about 1-2 months. The average attorney’s fee for this procedure is said to be around 300,000 yen for the retainer and 300,000 yen for the success fee according to information on the internet.

Retainer fee is around 300,000 yen, success fee is around 300,000 yen

In this procedure, it is possible to request the disclosure and deletion of the IP address at the same time. The above costs are for performing both actions. However, the cost will naturally vary depending on the content and volume of the post in question.

If the disclosed IP address was via an overseas proxy server

If the disclosed IP address was via an overseas proxy server, Japanese courts cannot sue the installer of the overseas proxy server.

At this stage, transitioning to legal proceedings requires specialized knowledge, so it is realistically difficult for an individual to carry out, and you will need to hire a lawyer.

②Prohibition of Log Deletion

Based on the identified IP address, we will next request the ISP (provider) to preserve the log (record) of the person who made the post using that IP address.

ISPs (providers) hold communication logs, but they do not keep logs forever and usually delete them after 3 to 6 months. Therefore, to prevent the log from being deleted during the sender information disclosure request, we will take procedures called log preservation provisional disposition request and sender information deletion prohibition provisional disposition request.

In practice, there are many cases where it is sufficient to issue a notice to the ISP (provider) saying, “We are making a sender information disclosure request, so please do not delete the log.” It is more efficient to consider issuing a notice first and then applying for a provisional disposition depending on the response.

③Request for Disclosure of Address and Name

We will file a sender information disclosure lawsuit against the ISP (provider) to request the disclosure of the poster’s address and name. Since the request for disclosure of address and name is important personal information, it cannot be done quickly with a provisional disposition procedure and must go through a formal trial.

If the connection was from a certain internet café

What is disclosed when an order to disclose the poster’s address and name is issued is strictly the “address and name of the line subscriber”, so if the post was made via an internet café, the address and name of the internet café operator will be disclosed.

Many internet cafes carry out member registration and identity verification in accordance with ordinances and industry association guidelines, but since internet cafés do not fall under the “specific telecommunications service provider” under the Provider Liability Limitation Act, they cannot make a sender information disclosure request, and further tracking becomes impossible.

We explain in detail about cases where identification is difficult in the following article.

④Claim for Damages

If the court issues an order to the ISP (provider) to disclose the address and name, it will become possible to file a claim for damages against the identified poster and claim for attorney’s fees and consolation money incurred in the series of procedures.

However, there are risks such as how much of the claimed damages will be recognized by the court and whether the other party has the ability to pay even if they are recognized.

Therefore, even if you win the lawsuit, you may not be able to receive sufficient compensation.


In order to identify a poster on the Shitaraba forum, multiple legal procedures must be undertaken.

Furthermore, considering the risks of not being able to identify the poster or not receiving adequate compensation even if identification is possible, it is necessary to carefully consider whether to exercise legal measures based on these risks.

These series of lawsuits are extremely complex and require advanced specialized knowledge. It is crucial to seek the assistance of a lawyer with a proven track record in handling online defamation cases and possessing high-level expertise.

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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