On an early spring day in 1834, the Hojun-maru bumped against an unfamiliar shore. The captain, 28-year-old Iwakichi, stepped outside with the last of what had once been the fishing junk's 14-person crew—just he and two teenage boys named Kyukichi and Otokichi remained.

The Hojun-maru had set sail from Japan on October 11, 1832, carrying a load of rice and ceramics for the Shogun. Soon after, a typhoon snapped the rudder, leaving the crew vulnerable to the water’s whims, and for more than a year, they drifted at sea, relying on the ship's supply of rice and rainwater to survive. Eventually, scurvy felled most of the crew.

The sailors didn't know it, but they had been at the mercy of the Kuroshio Current. Also known as the North Pacific Current, the California Current, the North Equatorial Current, and the “black current” for the deep blue of its waters, the Kuroshio begins in the Philippines and flows past Japan before turning toward California. This Pacific version of the Gulf Stream transports heat, salt, and nutrients, which creates the perfect conditions for fish-rich waters. And for the sailors of the Hojun-maru, the Kurioshio Current also proved to be a sort of watery conveyor belt that deposited them halfway across the world—near Cape Flattery, Washington.

The sailors and their ship attracted local Makah people, who enslaved them after salvaging remaining valuables from the wreck. In June 1834, Captain McNeil of the Hudson Bay Company was performing routine duties in the area when he stumbled upon the three Japanese fishermen living among the natives. The captain secured the release of two of the captives and later returned for the third, bringing them aboard his ship Llama [PDF]. The survivors eventually settled in China.

Little did they know that their story was not all that unusual.

A Current of Castaways

A monument near the Fort Vancouver Visitor Center honoring the three surviving sailors of the Hojun-maru.NPS // Public Domain

It was a man named Charles Wolcott Brooks who connected the dots. While serving as the Japanese Consul for California at San Francisco, Brooks began keeping records of wrecks that washed up on North America's shores. He noticed the junks all seemed to come from Japan, which was puzzling: The fishing ships purposefully weren't built for the open ocean—at that time, Japan was a mostly isolated country and wanted to stay that way—so the crews couldn't have sailed the ships across the Pacific without some kind of help.

In 1875, Brooks presented his research on the possibility of Japanese fishing boats making it to the New World on the "Kuro Shiwo" current to the California Academy of Sciences. “During seventeen years, in which I represented the Government of Japan … it has been my pleasure to devote much critical attention to the subject of Japanese wrecks, picked up adrift in the North Pacific Ocean and stranded upon the northwest coast of America,” he wrote. His research proved correct; the Hojun-maru is just one of several documented cases of Japanese boats swept to North America by the Kuroshio Current.

About 20 years earlier, the British brig Forrester had spotted the Japanese junk Takujo-maru floating 470 miles off the coast of northern Mexico. Three men from the original crew of 14 were still alive, including the captain, Jukichi. The junk had drifted for 18 months after getting caught in a violent storm and had twice come close to the California coastline, only to be driven back by the waves. The survivors spent the winter on an island in Sitka Bay, Alaska, which was afterward known as Japonski, or Japanese Island [PDF]. Upon returning to Japan, Captain Jukichi published a book about his ordeal—an impressive feat, as Japan's Sakoku Edict called for anyone who returned to the country after going abroad to be “put to death.”

Whether similar wrecks traveled to North America before the arrival of European settlers is debated. At the Ozette Indian Village Archaeology Site in Neah Bay, Washington, 42 iron tool hafts dating from the late 1500s and early 1600s were discovered, leading some archaeologists to speculate that the metal arrived via Asian shipwrecks.

There’s also the presence of woolly dogs in the Pacific Northwest. These small white dogs were kept by the Salish people for their prized fur, which was shorn and mixed with mountain goat hair to create prized woven blankets. A DNA analysis revealed that the dogs were most closely related to Japanese Shibas and Siberian Huskies.

The Kuroshio Current Today

In October 1984, the girls of a Natural Science Club along the shore in Choshi, Japan, and tossed bottles into the ocean. Over the next 20 years, those bottles would travel all over the Pacific Ocean, arriving in the Philippines, the Hawaiian Islands, and North America after hitching a ride on the Kuroshio Current.

Those bottles weren’t the only bits of trash the current helped spread. China and Southeast Asia account for half of all plastic entering the ocean; the current then transports that debris north to Japan. In 2021, Japan Agency for Marine-Earth Science and Technology discovered deposits of plastics on the deep seafloor where the Kuroshio creates whirlpools. Single-use items like bags and food packages accounted for over 80 percent of the garbage.

The path of the current is also shifting as ocean temperatures continue to rise. Since 2017, a weakened Kuroshio has meandered south before continuing on its usual pattern, creating unusually high summer temperatures in Tokyo. Its ability to create cyclones is also increasing. These changes have affected the fish population, which was already strained from the increased demand of industrial fishing.

The current continues to carry ships to surprising shores. In December 2020, a fishing boat that had been swept to sea during the 2011 tsunami that devastated Japan was found floating near Hachijo Island, nearly 180 miles south of Tokyo. After spending nearly a decade adrift, the Kuroshio Current had returned the empty vessel to Japan’s waters.