For the high-level sushi carefully created by Chef Pitak “Koko” Hermkhunthod at Namba Ramen & Sushi, the fish must be fresh. It comes every two days, flown in from the Toyosu Fish Market in Tokyo — whole fish to be cut by Koko and his protege, Chef Kai (a “preferred nickname,” he said) at the 36-seat restaurant in Naples.