Editorial and fact-checking policy
This is an unofficial English translation for reference. The Japanese version is the original and takes precedence in case of any discrepancy.
Last updated: September 20, 2026.
Responsibility
Natsufuyu is operated by Ryoichi Sasaki, who holds final publishing responsibility. Each guide identifies its editorial team, research method, source dates, use of AI and whether hands-on testing took place. The Japanese editorial policy is the original policy.
Evidence and useful recommendations
We start with the practical problem the reader wants to solve. For product capabilities, prices and terms, we use current manufacturer or service-provider documentation. We distinguish advertised capabilities from measured results, and labelled examples from actual customer experiences.
A recommendation explains what the product can change, the conditions it needs, the work it leaves to the reader, its costs and a reasonable alternative. An attractive rendering does not prove that furniture fits. An affiliate commission does not prove that a product is suitable.
Fact-checking and updates
Before publication, we compare material claims with their cited sources, check calculations and links, review advertising disclosures, and inspect the published page. Source dates refer to the information actually checked, not merely a working URL. Prices, plans and conditions can change; the provider's current checkout and terms determine the purchase.
We prioritize corrections affecting a reader's decision. Send a page URL and the disputed statement to support@natsufuyu.app.
Hands-on testing, images and AI
We do not claim testing, interviews or expert review that did not happen. Each guide discloses whether it is based on desk research. Original diagrams and hypothetical calculations are labelled; stock or AI-generated illustrations are not product-performance evidence.
AI may assist research organization, drafting and proofreading. It is not a source for a factual claim. Published product claims must be supported by the cited evidence, and public changes receive a separate review.
Affiliate links
Where we earn a commission, the guide explains that relationship near the content and marks the relevant links. Ordinary links to official websites are not presented as earning links. We do not claim a partnership while an application is unsubmitted or awaiting approval.
Commissions do not establish product rankings or guarantee benefits. We include free or non-affiliate alternatives when they answer the reader's problem.