Cut eggplants in halves vertically.
Make some diagonal cuts in the skin side.
Soak them in salted water and drain.
Dry eggplants with a paper towel.
Heat oil in a frying pan.
Put eggplants in the pan from the skin side first.
After a few minutes, turn them over and cook a few more minutes.
Mix soysauce, vinegar, and sake.
Place eggplants in a plate and pour the sauce over them.
Sprinkle chopped green onion over them.