I think that might be Katsuobushi (鰹節 or かつおぶし) on the rice. Katsuobushi is dried, fermented and smoked skipjack tuna which is then shaved into fish flakes. From what I have been told is that the process will take about 2-3 months for the tuna to be ready for shaving, When its ready for shaving it’s weight of the tuna will be less than 20% of the original weight and almost resemble a piece of wood.
In Japanese cuisine, both Katsuobushi and konbu are used to make dashi. Dashi is the broth that forms the basis of many soups in Japan.