The main and sub-trademark strategy refers to registering multiple trademarks on the same product. One is the main trademark that reflects the corporate image on various products, and the others are sub-trademarks used on a specific product. (Also known as slave trademark).
Use the main trademark to establish and enhance the reputation of various products, and use the sub-brand to imply the use, function, ingredients, quality, etc. of specific products, which complement each other.