This is not the fish roe. Karasumi normally means the cured and dried ovaries of grey mullet, one of the great delicacies of Japanese food and expensive everywhere. This is rice flour with sugar worked into it, formed into a bar, pressed into a wooden mold, turned out, and steamed for fifteen to thirty minutes.

There are two explanations for the name and they point in completely different directions. One says that in this landlocked part of Gifu, actual karasumi was an unobtainable luxury, so somebody made a sweet in roughly the same shape and called it the same thing. The other says the shape resembles a Tang dynasty inkstone that doubled as a paperweight.

In the Tono area it belongs to the doll festival in March, where it is set out as an offering, and it is also simply an everyday sweet that people eat with tea.

There is a custom attached to it called gandouchi, in which children go round the houses of the neighborhood on the day of the festival collecting sweets. This is the thing that used to be handed out at the door on that day. A landlocked village's substitute for a coastal delicacy, pressed into the hands of children walking from one house to the next.