Den is an izakaya near Gwangalli Beach in Busan that serves mackerel bo sushi, futomaki, and sashimi. The mackerel bo sushi is made with aged mackerel seared with a torch and finished with a light ginger aroma. Seafood dishes include futomaki, sashimi, uni, and grilled mero, and yuzu highballs are available as well. Portions are small and prices are on the higher side.