So far, the reviews are not bad. The intrepid folks over at Rocket News 24 gave the sweet-and-salty taste sensation a thumbs-up.
"Without a doubt, the sauce was the prominent flavour, but with the savoury note, it didn't taste like a dessert," a reporter at the website wrote. "Whatever the case, we couldn't stop putting fistfuls into our mouths, so it was definitely a winning combination!"
The "McFry Potato Chocolate Sauce" is McDonald's latest attempt to revive its flagging fortunes in Japan.
McDonald's Japan, which is half-owned by the American parent company, in November reported a net loss of $252 million for the first nine months of last year, its worst result since the company listed in Japan in 2001, Jiji Press reported.
The losses were partly the result of a series of food safety problems that have made customers wary.
In 2014, the burger chain admitted it had been selling expired chicken from China and started getting the meat from a supplier in Thailand. Then pieces of plastic were found in Chicken McNuggets that came from Thailand.
Around the same time, a customer found a tooth in their french fries. Separately, McDonalds had to limit customers to one small packet of fries each as labor disputes at U.S. West Coast ports interfered with shipments. Could the chocolate fries revive McDonald's fortunes here? Well some customers sure are happy. On Twitter, @ Ikuchy852 declared them "delicious."
But McDonald's isn't betting everything on the chocolate fries. It's also running a competition, offering a $11,850 cash prize to the person who comes up with the best name for its new burger, the Asahi Shimbun reports.
The tentative name in Japanese translates roughly to "Juicy beef hamburger with hot and soft potatoes from Hokkaido, cheddar cheese and burned soy sauce-flavored special onion sauce." Shouldn't be too hard to come up with something catchier.
