Intestingly enough, for all the fame of sushi and (California) rolls (maki), a very popular form of Sushi in Japan is almost ignored abroad.
Gunkan or “Mothership” in Japanese is a typically Japanese way of serving ingredients which would be difficult to serve on top of a nigiri.
They are usually made by wrapping a piece of “nori”/dry seaweed around a ball of rice/shari with plenty of space left on top to fill.
The advantages are multiple. The nori/seaweed is crisp. You eat the whole in one go with your fingers (clean your hand first!). And they make for beautiful decoration!
Some people do not appreciate the “nori”, but it could be replaced with very thin strips of daikon, cucumber, zucchuni and so on.
“Benisuwaigani” (Red Suwai Crab), “Mikkuriebi” (Mikkuri Shrimp, a variety of sweet shrimp, delicious in spite of the colour!), “Kobashira” (Muscle from the “Bakagai” Shellfish), “Nama Karasumi” (raw mullet roe)
“Ooenkogani” (Ooenko Crab, featuring body flesh, red brins and pincers flesh!), “Akahada Tsurutsuru”, a seaweed gunkan! It is a red seaweed variety), “Sakura ebi” (Sakura Shrimp, the pride of Shizuoka Prefecture!), “Nama Shirasu/Umeiwashi” (raw whitebait from “Ume” sardines)
For more about sushi check Shizuoka Sushi!