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.

Here are some samples of “gunkan” I have eaten over the years:

Ikura/Salmon roe Kani Salada/Crab salad Kanitsume/Crab pincers

Kobashira/Round Clam round twin muscles Mizuna/A Japanese thin leaf vegetable + quail egg Negitoro/finely chopped tuna and thin leeks

Shirako/Whiting-male cod sperm sacs Takuan/Pickled Japanese daikon + cucumber

“Shirako” (Cod Whiting) for a repeat.

“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)

“Gunkan” can be presented on individual plates for better effect!

The three above are varieties of sea urchins: “Bafun uni” and Murasaki Uni”, whereas the last last show both gunkan and nigiri.

Above are three types of crabs: “Egani”, Ibaraganimodoki” and Matsubagani”

Three shellfish varieties: “Kagabai”, Nejinakubai” and “Sazae” (Turbo Shell)

We go to fish varieties: “Hoteiuo” roe, “Konago”, and “Muroaji” (horse mackerel variety)

“Noresore” (baby conger eels), and two shrimp varieties: “Shiraebi” (white shrimp) and “sunaebi” (sand shrimp)

For more about sushi check Shizuoka Sushi!