Depicts all 12 of the magical sea creatures in the Luminous Marine Life series in silhouette. Air bubbles up between them and a tail fin disappears beneath the waves to the right. Surrounded by the country name and the denomination.

Depicts a broadband, reminiscent of a vintage porthole, and rames an aquatic scene that appears black and empty under normal light. However, when illuminated with ultraviolet light, several luminescent squid emerge, glowing in vibrant blue and purple tones, while a navigational element on the left shines green.

This is the second coin featuring a center that looks dark and empty under standard lighting but reveals a hidden spectacle when exposed to UV light—the firefly squid. Though small, this bioluminescent creature knows how to command attention. Its body is covered in tiny light-producing organs called photophores, which emit a mesmerizing blue glow. Each year, from March to May, the waters of Japan’s Toyama Bay take on an enchanting blue hue as these squid, typically found in deep waters, approach the shore to lay their eggs.

Despite their size, firefly squid share the same fundamental body structure as other cephalopods. They possess ten limbs—eight shorter arms lined with suction cups for grasping prey and two longer tentacles for capturing it. Their remarkable speed, achieved by expelling water to propel themselves forward, makes them efficient hunters in their deep-sea habitat.