The phrase "a special knowledge" is correct and usable in written English.
It can be used when referring to a specific type of expertise or understanding that is unique or not commonly held.
Example: "To excel in this field, one must possess a special knowledge of the latest technologies and trends."
Alternatives: "a unique expertise" or "a specific understanding".
Walter J. Hickel, at In terior, has claimed a special knowledge of youth.
And with it comes a special knowledge that can be accessed only through being and doing.
Oxford Dictionary definition of a charlatan: A person falsely claiming to have a special knowledge or skill.
We hoped to approach that complete account by harnessing the expertise of people with a special knowledge of, or information about, the emails.
He is a newspaperman, at present working on a Sunday tabloid, who has a special knowledge of British Fascism and has written a handbook on it.
Psychiatrists who contributed to "The Dangerous Case of Donald Trump" are moved by the sense that they have a special knowledge they need to communicate to the public.
And, as this Court has previously recognized, many events, while perhaps "adversarial," are not of such a nature that an attorney can provide any special knowledge or assistance to the accused as a result of his legal expertise.
The researchers investigated the computing systems inside a car without any special knowledge from the manufacturer.
Though "The Gift" features a few hallucinatory sequences that will please "Evil Dead" fans, it is essentially a psychological drama, about a psychic (Cate Blanchett) in a small Southern town whose special knowledge of a murder gets her in trouble with the law and her neighbors.
An alternative fact checker might wear a nose ring or a funky hat, or have special knowledge of a foreign culture, but the main thing is that he or she would get the job done.
"But it requires a lot of special knowledge".
