The difference between dark soy sauce and light soy sauce is as follows:

1. Different manufacturing processes: light soy sauce mainly uses soybeans or black beans and flour as the main raw materials, and is artificially seeded with yeast. It is made by natural exposure and fermentation. Dark soy sauce is a rich soy sauce made by adding caramel to light soy sauce through a special process.

2. Different colors: light soy sauce is reddish-brown, while dark soy sauce is tan and shiny.

3. Different usages: Light soy sauce is generally used for seasoning, and is more commonly used in stir-fried and cold dishes. Dark soy sauce is generally used to color food.