Hello, Suzuki063! Welcome to Japanese Wikipedia. If you are not a Japanese speaker, you can ask a question in Help. Enjoy! ウィキペディアの機能や使い方に関してわからないことがあったら利用案内で質問できます。 Suzuki063さんがウィキペディアにおいて実り多き執筆・活動をなされることを楽しみにしております。--Lmkjgmo（会話） 2023年1月20日 (金) 19:35 (UTC)[返信]
A primary source may be used on Wikipedia only to make straightforward, descriptive statements of facts that can be verified by any educated person with access to the primary source but without further, specialized knowledge.
Wikipedia articles should be based mainly on reliable secondary sources, i.e., a document or recording that relates or discusses information originally presented elsewhere.
Reputable tertiary sources, such as introductory-level university textbooks, almanacs, and encyclopedias, may be cited. However, although Wikipedia articles are tertiary sources, Wikipedia employs no systematic mechanism for fact checking or accuracy. Thus, Wikipedia articles (and Wikipedia mirrors) in themselves are not reliable sources for any purpose (except as sources on themselves per WP:SELFSOURCE).
Primary sources are often difficult to use appropriately. Although they can be both reliable and useful in certain situations, they must be used with caution in order to avoid original research. Although specific facts may be taken from primary sources, secondary sources that present the same material are preferred. Large blocks of material based purely on primary sources should be avoided. All interpretive claims, analyses, or synthetic claims about primary sources must be referenced to a secondary source, rather than original analysis of the primary-source material by Wikipedia editors.
When editing articles in which the use of primary sources is a concern, in-line templates, such as primary source-inline and better source, or article templates, such as primary sourcesand refimprove science, may be used to mark areas of concern.
Wikipedia:Identifying and using primary sources - Wikipedia
"Primary" is not, and should not be, a bit of jargon used by Wikipedians to mean "bad" or "unreliable" or "unusable". While some primary sources are not fully independent, they can be authoritative, high-quality, accurate, fact-checked, expert-approved, subject to editorial control, and published by a reputable publisher.
Primary sources can be reliable, and they can be used. Sometimes, a primary source is even the best possible source, such as when you are supporting a direct quotation. In such cases, the original document is the best source because the original document will be free of any errors or misquotations introduced by subsequent sources.
