Terms of Service

Last updated: April 30, 2026

These Terms govern your use of Cairn ("the Service"). By using the Service, you agree to these Terms.

1. Definitions

"Service"

The Cairn website and its writing/reading features.

"Entry"

A text of up to 50 characters submitted to the Service.

"User"

Any person who reads or writes via the Service.

"Operator"

The individual or entity operating the Service.

2. Nature of the Service

Cairn is operated as an online text-archive service. While the Operator donates a portion of net profit to public-interest organizations as a voluntary commitment, Cairn itself is neither a charity, donation organization, nor a registered non-profit entity.

1. The Service allows a User to acquire, in their lifetime, three Entries (the "three stones"). The first Entry ("Stone 1") is placed at purchase. The remaining two ("Stone 2" and "Stone 3") may be placed any time within the 50-year window (see Section 4-bis).
2. Entries cannot be edited or deleted by the User after confirmation, except under the limited conditions in Section 11.
3. Reading Entries is free and requires no account.

3. Eligibility to Write

1. Users aged 16 or older may register and write directly.
2. For persons aged 15 or younger, a parent or appropriate guardian may submit an Entry on their behalf via proxy registration.
3. The User self-attests to their age and name. The Operator may request production of identity documents after the fact where there is suspicion of fraud or duplicate registration.
4. To submit an Entry, a User must obtain one of the following:
   • Invitation code: a single-use, time-limited code issued by a User who has already completed their Entry.
   • Application lottery: registration in the Operator's free application form. The Operator sends invitations to applicants selected at random.

3-bis. Notebook Structure and Page Numbers

1. Entries are compiled into annual "Books" (e.g., Cairn Book 2026).
2. Upon confirmation, a sequential page number within that Book is assigned.
3. The page number and the content hash serve as permanent public identifiers.
4. If an Entry is deleted under Section 11, its page number is not reused; the page is marked as "(retracted)" and remains blank.
5. The Operator shall not issue Entries, page numbers, or content hashes as NFTs or any speculative financial instrument.

4. Fees and Payment

1. Writing requires payment. The User purchases three stones at $15, $9, or $3 based on the country at the time of purchase (per-stone × 3, PPP-based tiered pricing). See the Commercial Disclosure for the country list.
2. At checkout, Users may add an optional voluntary donation.
3. Payment is processed via designated providers (e.g., Stripe).
4. Of the base fee, after deducting payment processing fees, infrastructure costs, taxes, and other necessary operating expenses, up to 50% of the resulting net profit is donated to public-interest organizations. The remainder covers the Operator's compensation and future expansion of the Service.
5. Voluntary donation amounts are donated in full (100%), less only payment processing fees.
6. Donation recipients are reviewed every six months.
7. The Operator publishes a transparency report every six months and remits donations on the same cadence.

4-bis. Window and Lapse of Publishing Rights

1. Publishing rights are valid for 50 years from the time of purchase.
2. For the second and third uses, the User authenticates with their full name and proof key. No additional payment is collected.
3. Publishing rights not exercised within the 50-year window lapse. There is no refund for lapsed rights.
4. If the Service is shut down, no refund is issued for unexercised rights.
5. Publishing rights are non-transferable and are bound to the identity recorded at the time of purchase.

5. Publicly Displayed Information

After an Entry is confirmed, the following becomes public:

• The Entry text (up to 50 characters)
• Year of birth (4-digit year)
• Country (self-attested)
• Date of writing
• Display name (User chooses: real name / pen name / anonymous)
• Content hash (SHA-256)

Identity documents, contact details, and payment information are never public.

6. Intellectual Property

1. Copyright in each Entry remains with the User.
2. The User grants the Operator a worldwide, perpetual, royalty-free license to publish, reproduce, and distribute the Entry.
3. If the Service is shut down, the Operator will make reasonable efforts to preserve Entries in a permanently accessible form.

7. Prohibited Content

Entries must not contain:

1. Disclosure of others' personal information
2. Defamation or insult of a specific person or group
3. Incitement of hatred toward a specific person or group
4. Incitement or facilitation of illegal acts
5. Child sexual exploitation material
6. Glorification or incitement of terrorism
7. Commercial advertising or spam
8. Unauthorized reproduction of copyrighted works
9. Meaningless strings or machine-generated content
10. Any content the Operator reasonably deems contrary to public morals

8. Handling of Identity Verification Data

1. Any documents a User provides in response to a request from the Operator are encrypted at rest and never made public.
2. Such documents are not disclosed to third parties except: (a) in response to valid legal requests, (b) court orders, or (c) at the User's own request.

9. Proof of Authorship

1. A SHA-256 hash of the Entry is generated and publicly displayed upon confirmation.
2. Users may later request the Operator to certify their authorship using their original credentials.
3. Upon valid request, the Operator issues a "Certificate of Authorship."

10. Proxy Registration for Minors

1. Guardians may submit Entries on behalf of children aged 15 or younger.
2. The guardian and the child's identity are provided by self-attestation. The Operator may request production of supporting documents where necessary.
3. The public display will include: "Words of a child, [country] [year of birth], submitted by [guardian name]."
4. A child registered as a minor through proxy registration may, in adulthood, purchase their own three stones as an exception to the one-purchase-per-lifetime rule.

11. Deletion of Entries

The Operator may delete an Entry only in the following cases:

1. The Entry reasonably violates Section 7.
2. In response to a valid court order or legitimate law enforcement request.
3. The User designated post-mortem deletion during their lifetime, and death has been verified.
4. The User requests deletion and the Operator recognizes special circumstances (limited to once per lifetime, additional fee $100).

12. Disclaimers

1. The Service is provided "as is." The Operator makes no warranty of fitness, accuracy, or continuity.
2. The Operator is not liable for Entry content. Disputes regarding Entries are the responsibility of the writer.
3. The Operator is not liable for temporary or permanent service interruption due to server failure, natural disaster, war, or censorship.

13. Changes to These Terms

These Terms may change without notice. Updated Terms take effect upon posting. However, material changes to fees, refunds, or deletion conditions will be announced in advance, on the Service or by email.

14. Governing Law and Jurisdiction

1. These Terms are governed by the laws of Japan.
2. Disputes shall be subject to the exclusive jurisdiction of the Tokyo District Court as the court of first instance.