The endurance of Japan's simple street snack

BBC -- May 19
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."