What’s the farthest you’ve ever traveled for a sweet potato? It’s okay, you can take some time to think. For me, it was a nearly 11-hour flight to Japan to find a guy named Eroko, who installed a giant wood-fired oven on the back of his tiny roadster convertible and drives nighttime streets of Yokohama, selling hot sweet potatoes.

While the yam car wasn’t the sole reason for my entire trip to Japan — I also went for the gyoza, the sightseeing, and more gyoza — it was definitely what yanked me over to Yokohama, which is about 17 miles south of Tokyo’s Shinagawa Station. For the New Yorkers in the crowd, that’s roughly the same distance from Union Square in Manhattan to JFK International Airport in Queens. If this sounds annoyingly far, note that it’s actually only — gasp — an 18-ish minute subway ride away.

Eroko’s oven-car is officially called the RodoPot, a portmanteau of roadster and potato. I first encountered Eroko, who has been going by the name Lord Rod, via a 2018 Jalopnik article about him. He was initially inspired to make a sweet potato car when, as a kid, he saw a bulky Toyota Century sedan cooking and selling noodles. So, many years later, he invested ¥500,000 ($4,700) to convert Mazda Miata NC into a mobile, 125-horsepower, yam-hucking machine. As for why he went with roasted sweet potatoes specifically, well, they’re a popular street food in Japan (they call the dish yaki-imo), and there is a rich tradition of vendors selling them out of stands and food trucks.

The RodoPot.

I became sort of obsessed with Lord Rod and his RodoPot in part because he and his contraption combined two of my interests: sweet potatoes and Miatas. The former, because they’re tasty treats. The latter, because they’re cheap and unpretentious, an everyman’s sports car. There’s an appealing compact efficiency to them. To me, RodoPot made total sense. Why use a whole big food truck when a small car will do?

Plenty of others agree. Lord Rod has developed something of a fanbase in Japan, especially online. He tweets from the account @EL_Loco2018; his feed mostly consists of retweets of customers’ photos, their snacks held out with all their guts exposed in their delicious glory.

There’s also a fair amount of fan art about him. Like, check out this knitted car:

And this custom, hand-crafted scale model of RodoPot, featuring a detachable oven with a functioning lid. There are even tiny little sweet potatoes inside.

On the days when he’s cooking, the routine goes something like this: Lord Rod tweets out a location and a time, usually including a screengrab from Apple Maps for reference.

About an hour or so before he opens, he’ll tweet out a live Periscope broadcast featuring dashcam video of him driving over to the spot, winding through the streets of Yokohama, blasting music.

When I finally got a chance to visit him back in March, I couldn’t find him at first. I checked my Twitter feed to find that he was running late. Then I heard the distinct roar of a Miata engine and looked up to find him driving by. Someone watching his Periscope stream would have witnessed me gawking, stupefied, and then suddenly concerned, as he continued driving by, disappearing around a corner.

I ran to catch up, worried that I wouldn’t be able to find him again, or even be able to ask anyone for directions. I cut through an alley, turned the corner, only to find he was gone.

Or so I thought. After a few seconds of despair, I turned around to find that he had parked on the shoulder of a bridge directly behind me, under a freeway overpass, and already had a few hungry customers waiting.

I casually walked over, trying to hide my eagerness. Lord Rod had the oven lid open and was checking on his wares. He wore a gray hoodie with a tan coat and apron over it. The oven glowed red and one of the heat pipes was dented slightly. The back window of the convertible top was lightly dusted with soot from the oven. Inside the car, there were sunglasses on the dashboard and assorted supplies on the passenger seat — boxes of sweet potatoes, rolls of foil. On the driver’s seat sat a red bandana.

Lord Rod announced something out loud to everyone waiting in Japanese, and sensing my total lack of comprehension, said something to the three other guys waiting with me. One of them took out a phone, tapped something out, nodded at it, then showed it to me. It was a Google Translate page, the English output reading, Please wait 20 minutes. I nodded, finally understanding, and they all laughed.

Lord Rod at work.

It was about 7 p.m., and people were passing by, coming home from work. Most stopped to ponder the car and the oven. One woman who drove by took photos from her car as Lord Rod triumphantly posed.

Eventually Lord Rod nodded yes, the sweet potatoes were ready, and I put in my order. He had recently printed stickers (Japanese text reading Lord Rod!), so I got one of those too, all for only ¥1300 (about $11.98). After I paid, I opened my phone and showed Lord Rod a photo of my own car — I had pretty recently gotten a cheap, dark-green rust bucket that’s an earlier model of his convertible — to which he responded excitedly, “Miata!” But, with the language barrier, that’s unfortunately where the conversation ended.

Lord’s yams are wrapped in foil and handed out in brown paper bags. They smell like burning wood. You eat them like a Mission-style burrito, folding the foil down every couple of bites. There’s some char on the skin, with a nice campfire taste. Inside, they’re just buttery enough so that each bite is fluffy and pleasantly gooey, but that nothing drips onto your shoes. They’re hot enough for you to singe your mouth, and tasty enough to risk it.

The author’s potato, in all its glory.

The other guys shared one sweet potato between themselves, which was probably a good idea. It was enough to be a whole meal. About halfway through I decided to give up, folding the foil back up around it so I could snack on it later.

As I left, two elderly women walked by arm-in-arm. They seemed delighted by the whole car-oven setup. They took some photos, then ordered a sweet potato to share. The general concept is pretty ridiculous, but it’s hard not to be charmed by it.

And yet it’s also treated with an intense seriousness — his food is really good. It’s not surprising that Lord Rod has gained such a cult following. In March, he announced he was hiring “three to five” employees to help expand his mobile sweet potato empire, and more recently, he got a second (pink!) RodoPot. Imagine, an army of tiny convertibles with ovens strapped securely onto their luggage racks, torching buttery sweet potatoes to perfection, zooming around a distant city, feeding all who are tired and hungry and have ¥800 to roast. All hail Lord Rod.