It's been two years since Doug Ostrem found a Japanese glass fishing float along O'ahu's northeast shore, but he still gets excited when he tells the story. He arose that day at sunrise with his wife to go beachcombing and quickly noticed several round plastic floats strewn across the sand. Then he spotted one that looked different. "This big, green glass float was just sitting there!" he says.

For Ostrem, a clothing salesman, finding this basketball-size glass ball was the high point of his fifty-year career as a beach-comber. Naturally, he had to show it off. So he carefully put it in his car and rushed away to visit his brother and then some friends. “Boy, were they jealous,” he says. “It was great!” Decades ago beachcombers in Hawai‘i and throughout the North Pacific regularly found glass balls deposited on shore by wind and waves. Sometimes a dozen or more would wash up all at once. From around 1910 into the 1960s, Japan’s glassblowers turned out vast quantities of these surprisingly durable orbs for the nation’s fishing industry. China, Korea and other Asian nations also produced their share. Some inevitably broke loose from the nets and lines they buoyed, riding the North Pacific’s endless merry-go-round of currents before eventually finding their way back to terra firma.

As plastic gradually replaced glass in the making of fishing floats, the appearance of glass balls on Pacific beaches began to decline. Finds like Ostrem’s are now rare indeed, especially on Hawai‘i beaches. But those in the know will tell you that there are still plenty of glass balls out there waiting to be found by the faithful, the lucky and those who know where to look.

The first person to write authoritatively about glass balls—and the first certifiably obsessed collector—was Amos Wood, an aviation engineer from Ohio who moved to Seattle to work for Boeing and ended up falling in love with beachcombing. “It’s a tremendous thrill to find a ball that you know has traveled thousands of miles at the whim of wind and current,” Wood wrote in his 1967 book, Beachcombing for Japanese Glass Floats, a bible for collectors.

Wood described how glass balls travel in mostly clockwise patterns around the North Pacific, carried by the interconnected currents of the North Pacific Gyre. The ones that don’t come ashore or slip into sub-gyres travel in a great loop from Asia to North America and back again. Wood pioneered the concept of “gyre memory,” which postulates that ocean gyres eject their floating debris at predictable rates. Using this theory, production data he gathered from Japanese glass factories (he found that six million glass floats were produced in 1966 alone) and a guess at loss rates, Wood estimated that some ten million glass balls were circulating in the North Pacific at the time. By his ballpark calculations the last of those glass balls won’t wash ashore until 2145.

Oceanographer Curtis Ebbesmeyer has inherited Wood’s mantle as the foremost tracker of the paths traveled by glass balls. He has made a career of mapping the ocean’s currents, using everything from corpses to lost shipments of hockey gloves to gather data points. In his book, Flotsametrics and the Floating World: How One Man’s Obsession with Runaway Sneakers and Rubber Ducks Revolutionized Ocean Science, Ebbesmeyer describes how he calculated the time it takes for each gyre to make one circuit (6.3 years for the North Pacific Gyre) and what percentage of the gyre’s content is shed with each orbit (approximately half). “Suppose you count 100 million glass balls, all released at once,” he says. “After one revolution there will be 50 million. Then you take half, half, half and half, on and on. You come up to the present day, and you find out that there are probably millions still out there.”

Many of the world’s glass balls are stranded in places like mangrove swamps in southern Japan or on remote beaches in Alaska, Ebbesmeyer says. He also believes that there are a few million stuck in the Great Pacific Garbage Patch, the notorious vortex of trash between Hawai‘i and California. More than one person sailing through the Garbage Patch has told him that they found so many glass balls there that they ran out of room in their sailboats to carry them. Updating Wood’s calculation, Ebbesmeyer estimates that the last glass float will hit shore in 2177, although he adds, “Neither Amos nor I will be around to check the results.”

Japanese glass floats range in size from golf ball to beach ball, and most come in shades of green, echoing the hues of the sea, although colors such as amber, blue and red are sometimes found. Most are round, although some are shaped like rolling pins. The glass, typically made from recycled beer or sake bottles, is thick and sturdy and often filled with bubbles and other imperfections. Sake apparently went into glass ball production in other ways, too: There are reports of people who have accidentally broken glass balls noticing a whiff of sake in the air afterward—a reflection of what might have been on the breath of the glassblowers.

While a fragile material like glass might seem an unlikely choice for the manufacture of industrial fishing gear, glass balls are rugged, even when stripped of their protective rope netting. During the magnitude-7.0 earthquake that shook Alaska in 2018, several glass balls rolled off the shelves in Kevin Easley’s Anchorage dental office. To his surprise, all but two survived the seven-foot fall. The others just bounced off the floor, unscathed.

Easley is an avid beachcomber who has hunted for glass balls along Alaska’s shores since he was a kid. He’s also a bush pilot, and for the past ten years he’s spent time beachcombing along the Gulf of Alaska’s Lost Coast, where he lands his Cessna 185 on remote beaches to camp. He brings his fat-tire bike to cover lots of ground, and he says he’s had more luck finding glass balls this way than ever before.”Some of them are really tough,” he says. “I’ve seen balls rolling up and down for a hundred yards through minefields of sharp rocks and boulders—and they make it through the gauntlet.”

Of course, tough as they are, not every glass ball that washes ashore survives in one piece. All that might be left for a beachcomber to find is the glass plug used to seal the sphere. Noni Sanford, a Hawai‘i Island artist who lives in Volcano village, calls these chunky bits of glass “piko,” the Hawaiian word for navels. Sanford frequents Kamilo beach, a.k.a. “Trash Beach” or “Plastic Beach,” a rocky stretch of coast near South Point where massive amounts of marine debris from the Great Pacific Garbage Patch wash ashore. She has found dozens of glass-ball piko there.

Some have been polished smooth by the sand and sea, and these she displays at home in glass bowls like jewels. Others, fringed with jagged glass, look like menacing starfish, and these she has hung from the eaves of her garage. Some of them bear kanji identifying the factory that made them or the fishing fleets that used them. She estimates that nine out of ten glass balls that land at Kamilo shatter on the rocks, leaving only the piko. Still, she has found many intact, including—remarkably—eight last year on Christmas Day. “It was a complete miracle,” she says.

Not all collectors have experienced the thrill of finding a glass ball in the wild. Take Bob Silva, for instance, a retired Honolulu police officer who owns more glass balls than he can count—all of them found via the internet. In every nook and cranny of his nautically themed Kailua home, you see glass balls. They’re on the bookshelves; they fill large flowerpots and decorative baskets and bowls. They’re built into an end table, and one especially valuable specimen sits in a custom-made wooden display rack. They hang from the ceiling in his garage and under the rafters outside his home office window. They hang all around his courtyard and from the roof of the rustic gazebo beside his pool.

Silva started amassing them after heart surgery left him homebound and feeling exceptionally mortal. The thrill of the on-line hunt kept him going. “If I could find one for under $100 including shipping, I was doing good,” he says. Altogether, he’s spent more than $20,000 on glass balls. “I guess you might say it was my midlife crisis. Some guys buy fancy sports cars. I bought Japanese fishing floats.” Those days are behind him now. “I got word from the boss—my wife—that we’ve got too many,” he says. Still, he periodically looks at what’s for sale on Craigslist or eBay—“Just to see what’s out there,” he says.

Glass balls selling on sites like eBay typically range in price from about $15 to $300, but unusual floats can go for much more. According to Alan Rammer, an expert collector who lives along the Washington coast, price is determined by size, shape, color and/or markings. “Most people believe when they have a large glass float, they have found a nest egg to retire on,” Rammer says, “but those are actually quite common.” On the other hand, he says, a small, misshapen, atypically colored float with an unusual maker’s mark can go for thousands of dollars. He knows of a rolling pin-shaped float with unique kanji that sold for $8,500.

Honolulu-born Daniel Oh, an Air Force pharmacist stationed at Yokota Air Base, west of Tokyo, moonlights as an online dealer in glass balls. After being transferred to Yokota a couple of years ago, Oh became fascinated by the history of the floats and their role in the livelihood of Japanese fishermen. And then he went treasure hunting to see if they could still be found.

On his first venture he pulled an all-nighter, leaving for northern Japan after work and arriving at the beach around 5 a.m. After half a day of hunting, he found a glass ball the size of a basketball. “It was over after that,” he says. “I became addicted.” He estimates he has collected two or three thousand glass balls since then. Some he has found washed up on the beach, some buried in the sand. Occasionally he strikes gold and finds abandoned stock-piles of them overgrown with vegetation.

He’s collected so many glass balls he’s run out of room to store them. “My shed is almost falling apart because there are so many floats pushing against the walls,” he says. To keep his inventory in check, he started selling them through Facebook, mostly to people in Hawai‘i. “Hawai‘i people are sentimental about them,” he says. “And I just want to share my hobby.”

Not all of the stockpiles of glass balls in Japan have been abandoned. Eighty-one-year-old octopus fisherman Mutsuo Domon’s fishing gear includes about a hundred glass floats. “I inherited all of them from my father, my grandfather and my great-grandfather,” Domo says. “I was told that my great-grandfather purchased most of the glass floats from the fishing supply store. And now fishing supply stores don’t carry the glass ones anymore.”

Domon, who lives on Hokkaido, has fished for octopus there since he was 15. He works near shore, setting a series of vertical lines with upright hooks that rest on the ocean floor, using pebbles as sinkers and tiny glass floats—each a little smaller than a tennis ball—to hold up the rope connecting the lines.

Until about thirty years ago, when he switched from the use of rope made of natural fiber to rope made from synthetic fiber, he periodically lost floats to the sea.”On average I lost one glass float a year, because the ropes became rotten and broke and the glass floats would drift away,” Domon says. Now he loses them only when he accidentally breaks one, which is rare.”They are hard to break,” he says. “I believe they will last more than a century if you handle them carefully.”

While Domon depends upon glass balls to make a living, he’s not immune to the qualities that enchant glass-ball collectors the world over. “Glass floats look beautiful to me,” he says. “Maybe that’s one of the reasons I still use them.” Some of his fellow fishermen have suggested the iridescent globes mesmerize octopuses, making them easier to catch. But Domon just shakes his head. He doesn’t buy that theory. “Octopus aren’t that stupid,” he says. HH

Susumu Michizoe and David Thompson contributed to this story.