Nigiri (hand pressed) refers to the practice of hand pressing the sushi into a small rice ball. Other ingredients are then pressed along with the nigiri sushi to be consumed entirely in a single serving.
Chirashi (scattered) is a simple form of sushi which is sushi placed in bowl with the other ingredients scattered on the top of the rice. These ingredients are eaten along with the rice using a non-metal spoon. Despite its literal name, ingredients are often carefully placed and presented in a display of colors and shapes pleasing to the eye when presented to customers.
Maki (roll) sushi in which the rice is enclosed in a wrapping of dried seaweed (Nori). Traditionally Makisushi is rolled into a tube form using a specialized roller. There are many variants of Maki Sushi, with Temaki and Gunkan Maki being the more common ones.
Gunkan-maki (Gunship roll) is named so due to its shape resembling a gunship. The sushi is rolled into its nigiri form before having long sheets of nori wrapped around the sushi to form a container like form in which ingredients is then put on the rice. The nori forms like a 'wall' to prevent ingredients from spilling.
