About 4 dozen bamboo skewers soaked in water to prevent burning on grill
To make the rub:
Pulverize star anise, coriander, parsley flakes, dried chives, tobarashi, garlic powder, and salt with a mortar and pestle, in a spice mill, or with a coffee grinder dedicated to spices. Coat shrimp with rub, cover and refrigerate for 1 hour.
For the Ponzu sauce:
Mix soy sauce, vinegar, brown sugar, lemon juice, lime juice, ginger juice, and chives and make sure brown sugar has dissolved. Add parsley and refrigerate.
Heat grill. Skewer shrimp and grill them until they are pink and just turn opaque. Place in a nonreactive container and cover with Ponzu sauce. Chill for 2 hours before serving.