Cut off the tail end of okras. Peel off the hard part around okra end shown in the picture below.
They should look like this. Tip: If you cut the end completely, water gets inside.
Bring enough water to a boil. Sprinkle kosher salt over okras and rub gently on the cutting board. Tip: This brings out the bright color of any green vegetables (such as cucumbers) and removes the bitter taste.
Once the water has come to a boil, put in the okras (without removing the salt) in the boiling water and blanch for 1-2 minutes.
Drain and let cool the okras in iced water. As soon as they are cool, remove from the water and squeeze gently to remove excess water. Set aside.
In a small saucepan, add mirin and let the alcohol evaporate for 1-2 minutes.
When there is no more alcohol smell, add dashi and soy sauce. Once it boils, turn off the heat and set aside.
Transfer the okras to a shallow glass baking dish. Pour the marinade into the dish while the marinade is still warm. Let steep at room temperature for at least 1-2 hours before serving.
Plate okras on a serving dish, drizzle some marinade over the okras, and sprinkle katsuobushi. You can serve it at room temperature or chilled. Enjoy it within 2 days.