Peel shrimps and remove the tails. Devein shrimps by making a whole slit along the back of the shrimp and remove the vein with the tip of a knife or your fingers and discard it. Sprinkle salt and pepper over the shrimps. Massage them with potato starch.
Separate the broccoli into florets. Peel the broccoli stem thickly and cut it into strips. Wash a potato well and cut it in half lengthwise and then into half moons approx. 0.4 inch (1cm) thick.
Combine [A] in a bowl.
Fry the sliced potatoes in a pan with sesame oil (1/2 tbsp) over medium heat and sprinkle salt. When they become golden-brown, turn and put broccoli on potatoes. Add water and cook in low heat with a lid on top for 3 minutes. Heat without a lid until the liquid has evaporated. Remove the potatoes and broccoli from the pan.
Fry shrimps with sesame oil (1/2 tbsp) in the same pan for 2 minutes and put the potatoes and broccoli (from Instruction 4) back in the pan. Remove the pan from heat. Combine with [A] (from Instruction 3) and serve with dried bonito flakes on top.