During the summer, Ishikari Beach in the Ishikari region of western Hokkaido is a popular destination for sea bathers. But by late October, when they're long gone, another group of people can be seen crowded together on the sand, peering at it intently as they walk.

This new cohort are beachcombers, who search for and collect objects washed ashore — from pumice stones, created by volcanic eruptions 40,000 years ago, to a helmet decorated with Russian letters or an argonaut, a type of octopus housed in a shell that lives in warm, open-sea waters.

Why are these things here? What is special about them? This reporter took a walk along with beachcombers on Ishikari Beach, which is known as a popular beachcombing spot.