Koji is a traditional Japanese ingredient used in the fermentation process to create fermented foods such as soy sauce, miso, and sake. It is a type of fungus known as Aspergillus oryzae that breaks down starches and proteins into sugars and amino acids, resulting in a unique and complex flavor profile. Koji is often referred to as the "miracle mold" due to its ability to transform everyday ingredients into rich and flavorful products. It is also believed to have numerous health benefits, including improved digestion and gut health. Koji has gained popularity in recent years as a key ingredient in modern culinary creations and is celebrated for its umami-rich taste and versatility in cooking.