The Endurance of Japan’s Simple Street Snack
Eaten right off the coals, yaki-imo (roasted sweet potatoes) are a beloved centuries-old food, whether they’re served by old-fashioned street vendors or modern “imo” girls and boys.
“Yaki-imo…” The forlorn cry of the roasted sweet potato vendor echoed through the canyons of concrete and tiled buildings in a Tokyo suburb. The pre-recorded song, bookended with spoken claims of “oishii, oishii” (delicious, delicious), flowed from speakers on a stubby flatbed kei truck. This small vehicle, a ubiquitous part of working-class Japan, had been converted into a vessel for idōhanbai (literally, mobile sales).
Complete with an oven and an awning, plus a price list and colourful advertising, the truck trundled slowly around the perimeter of a park on a chilly March evening. It paused outside an apartment block, engine idling. A mother and child stopped, and, after a brief exchange with the vendor, they sauntered off with warm sweet potatoes in hand. The truck lingered a moment longer and then slowly drove on. The song, its rising and falling intonation like a lament, started up again: yaki-imo…
In a country better known for its sushi, sashimi and noodle dishes, the simple roasted sweet potato – or yaki-imo – doesn’t garner as much attention. But this hearty vegetable, yet another import in a sizeable list of historical introductions to the island nation (ramen, for example), has long been a beloved winter snack eaten in the cold months after its harvest. A favourite in Japan since the 1600s, yaki-imo’s moist, chewy texture and burnt-caramel scent still inspire nostalgia – as do the trucks that are gradually disappearing as sweet potato sales move to convenience stores and supermarkets.
“It is quite a rare treat to hear the song of those travelling peddlers,” said Aiko Tanaka, food researcher and director of the Japan Food Studies College in Osaka.
Indeed, not only are fewer kei trucks out there, but you may not even hear them coming. “The biggest factor behind the decrease in the song is noise complaints,” said one vendor, Kōki Ono, who has been selling sweet potatoes for almost two years. “Plus, hiki-uri sales [those from mobile peddlers in general] are also declining.”
Asuri Kamatani, president of modern yaki-imo outlet Himitsu na Yakiimo (Secret Roasted Sweet Potato), has noticed the same thing. “Certainly, compared to the Showa era [1926-89], the ojisan [uncle] with his roasted sweet potato truck is rarely seen,” she said. “It’s not an easy profession because it requires physical strength and time. So, it’s a tough job for older people.”
Those who still trundle along have had to adapt. Ono’s truck, Oono-ya, haunts busy spots along the Odakyu Line, a railway route that stretches from Shinjuku to the south-west suburbs of Tokyo, and the Nambu Line that serves Tokyo’s Ota Ward and parts of neighbouring Kawasaki. “The simple style of yaki-imo hasn’t changed much,” he said, the signage on his truck revealing that the potatoes only come in small, medium, large or oversized, with no condiments. One thing he has changed, though, is his strategy: emblazoned on Ono’s truck is a Twitter bird and a QR code, anachronistic additions to an otherwise retro sales method and snack.
Sweet potatoes originated in Central and South America, and scholars have some theories that they came to Japan in approximately the 17th Century. “The earliest historical reference to sweet potato in Japan seems to be in the diary of Richard Cocks in 1615,” said Eric Rath, professor of Japanese history at University of Kansas and author of Japan’s Cuisines: Food, Place and Identity. Cocks, the director of the British East India Company’s outpost in Hirado, wrote that he’d received the potatoes from honorary samurai William Adams, recorded as the first English person in Japan.
Rath said there’s some evidence they might have already been available in the Ryukyu Kingdom (today’s Okinawa) as early as 1605, via the Philippines and then China. Another account holds that in 1611, Ryukyuan King Sho Nei sent a gift of sweet potatoes to Satsuma Domain, a powerful political entity in southern Kyushu, which had invaded his kingdom and taken over his land – one result of which is that the orange tubers sometimes still bear the name satsuma-imo (potato from Satsuma).
Regardless of their path to get there, over time, roasted sweet potatoes proved very popular in Japan. Stalls were set up at the main guard buildings in post towns along important highways, and their sweetness and aroma – and their affordability – caught on. Signs at stalls sometimes advertised them as “kuri-yori-umai” (better than chestnuts). “In Tokyo, many ate them mixed with okayu (porridge made of rice and barley),” Rath said.
