Daikon oroshi might be
described as the Japanese answer to parsley. It is a popular garnish
served in Japanese restaurants. It consists of grated bits of the
daikon radish. Daikon oroshi is often mixed with sauces. The
device used to grate the radish is called an oroshigane (おろし金).
Closely related to daikon
oroshi is the word tsuma, which is a more general term for
garnish. This word is the source of a common Japanese metaphor: sashimi
no tsuma (garnish for sashimi) Sashimi (thinly cut strips of raw fish)
is often served with a garnish such as daikon oroshi. However, the
garnish itself is of little consequence.
Therefore, if someone says that
his presence at a meeting was “garnish for sashimi” he means that his
presence was of little meaning for the meeting. This metaphor is often
used as a tongue-in-cheek method of self-deprecation.