The primary ingredient in a traditional sushi roll is vinegared rice, known as "shari" in Japanese. This rice is typically short-grain, sticky, and seasoned with a mixture of rice vinegar, sugar, and salt. It serves as the foundation for sushi rolls, allowing them to hold together when rolled with other ingredients. Various fillings, such as fish, vegetables, and seaweed, are commonly added to create different types of sushi. The combination of texture, flavor, and freshness makes sushi a popular dish around the world, appreciated for its aesthetic appeal and culinary artistry.