Registering an artist name as a trademark
A stage name is not protected on its own. Someone else registering a name you have used for years happens more often than you would expect.
Using a stage name for years does not automatically create a complete monopoly over it. In Türkiye trademarks are registered under Industrial Property Law No. 6769, before TÜRKPATENT.
Which class
A trademark application is classified by the goods or services it covers. For a musician the essential class is normally the one covering live performance and entertainment services; if you intend to sell recordings or merchandise, the relevant goods classes need adding too. Registering in a single class may not stop someone using the same name in another.
Process and terms
Once an application passes examination it is published in the Official Trademark Bulletin and opened to third-party opposition. Registration runs for ten years from the application date and can be renewed indefinitely. A registered mark has to actually be used; a mark left unused for a long period can be challenged for revocation.
Why early
Registering after a name has become well known is both more expensive and riskier: an identical or similar application may already have been filed. Starting registration while an artist is still on the way up is one of the cheapest insurances in a career.
This piece is general information, not legal advice. Work with a trademark attorney before filing.