Pour the dashi, mirin and soy sauce into a small sauce pan.
Stir in the ginger.
Bring to the boil then leave to simmer, uncovered, for two to three minutes.
Turn off the heat.
Place the sauce pan in a bowl of iced water to cool. Set aside.
Heat enough cooking oil in a wok or frying pan to reach a depth of at least three inches.
While the oil heats up, cut the eggplants into rings about an inch thick. If your eggplants are thick, cut into halves vertically before slicing.
When the oil starts to smoke, dump in the eggplants and cook over high heat just until softened but not mushy. Tip: the frying time should take about two minutes or less.
Scoop out the eggplants and spread on a shallow bowl. Pour the cooled sauce directly over them.
Fry the bonito flakes in the hot oil for about 10 seconds.
Scoop out the bonito flakes and spread over the eggplants.
Serve immediately.