Chirashi sushi is a type of sushi where various ingredients are placed on top of sumeshi (vinegared rice). The word "chirashi (散らし)" in Japanese means "scattered," referring to how the toppings are sprinkled over the rice. With its vibrant colors, chirashi sushi is often served on celebratory occasions, particularly during Hinamatsuri (雛祭り, Girls' Day on March 3rd).

The ingredients used in chirashi sushi vary by region. In the Edo-mae style (common in the Kanto region), slices of sashimi are placed on top of vinegared rice and served in individual bowls. This style is also known as Edo-mae chirashi or Nama chirashi. Although it looks similar to kaisen-don (seafood rice bowl), the key difference is that chirashi sushi uses vinegared rice, whereas kaisen-don uses plain rice.

Outside of Kanto (especially in Kansai), sashimi is rarely used. Instead, shiitake mushrooms, kampyo (dried gourd strips), and abura-age (fried tofu) are simmered in a sweet sauce and mixed with vinegared rice. The dish is then topped with generous amounts of kinshi tamago (錦糸卵, thinly shredded egg crepe), pickled lotus root, boiled shrimp, and salmon roe for decoration. It is typically served in a large wooden container called a sushi-oke (寿司桶) and shared among diners. This style is also known as bara-zushi (ばら寿司), gomoku-zushi (五目寿司), or maze-zushi (混ぜ寿司).