"Long onion." Longer and thicker variety of negi (welsh onion). Also called shironegi, "white onion." Has a larger amount of white stem (lengthened by heaping soil around the stem when growing it).
The white part is used in yakimono (for example, negima, the yakitori of chicken with onion), agemono (for example, kushikatsu) etc.
The white part has a strong onion taste, but becomes sweeter when boiling and is therefore used in nabemono.
The green tubular blades are used in the same way as negi, by finely chopping them and using them in soups, dips, as a garnish etc.
[Naganegi. Photo Ad Blankestijn]