Burger King black burger in Japan: What the Kuro Burger tastes like

Japan has Mos Burger, the home of the burger with the rice patty instead of bread bun, but the hype and publicity surrounding the arrival of Burger King Japan's Kuro Burger –"black burger" because of its distinctive onyx-coloured buns and tarry black cheese – would suggest this is the burger's second coming. But is the hamburger chain, to put a pun on it, telling a whopper?

Not exactly. Burger King Japan first debuted the Kuro Burger under a concept of "irrationality" in 2012 [as you do] to celebrate the chain's fifth birthday in Japan (and on the subject of second comings, this is the chain's sophomore stint in Japan, after being forced to pull out in 2001 after losing a price war with McDonald's and other fast-food chains). The Kuro Burger Mark I featured the same jet-black buns and cheese, coloured similarly through the use of bamboo charcoal, and special onion-garlic sauce tainted by squid ink; the hamburger chain says the original Kuro was the chain's best-selling debut item that year.

The burger's latest reincarnation, only available across Burger King branches in Japan until November, comes in two versions, both of which feature liberal lashings of black pepper added to the hamburger mix: The plainer Kuro Burger Pearl (¥480), and the Kuro Burger Diamond (¥690), with added lettuce, tomato, onion and mayonnaise.

I learn the Pearl and Diamond cheeseburgers come smothered in the same distinctive tangy sauce – Shalyapin sauce, named after, and created for Russian opera singer Feodor Ivanovich Chaliapin aka Fyodor Shalyapin, who was touring Japan in 1936. The bass singer was suffering from a toothache, and a hotel chef devised a way to cook an extra tender steak for him. This dish, steak marinated in and covered in a minced onion and mirin sauce, is known in Japan as a Chaliapin Steak to this day.

"It's the sauce that makes the burger," says local government employee Takahiro Yoshi as we chow down on our burgers at Burger King in Otaru, Hokkaido, a picturesque yet industrial seaside town most famous for its fresh seafood and sushi, "The bun and cheese look interesting, but really there's nothing special, although I guess this burger is more peppery than other Burger King offerings. I eat at Burger King a few times a week, so I'd order it again though if I was in the mood."

I have to somewhat agree with Yoshi's assessment. The bun of my Kuro Pearl burger, though springy, offers only the subtlest hint of bamboo charcoal. That said, the bread is pleasantly more savoury than usual fast food burger buns. Likewise, the cheese slice perched atop my meat patty give no clues to its blackened origins, but there's definitely a peppery aftertaste to the burger as a whole, and the piquant, barbeque-like sauce is what holds the experience together. However, I'm unsure I'd repeat the experience. Perhaps it tastes better with salad, aka the Kuro Diamond?

"The Kuro Diamond is proving more popular, I guess, because it's more colourful and has added the added health benefit of vegetables," says an Otaru Burger King employee, mere days into the burger's promotion. "Customers have said they like the combination of the mayonnaise and Shalyapin sauce."

Indeed, while reactions to the black burger outside of Japan have been mixed, with most armchair critics commenting on how unappetizing it looks, in Japan, such attitudes hold little sway. Various types of seaweeds, beans and sesame foodstuffs in the traditional Japanese diet are black, while blackened onsen eggs cooked in pits of bubbling sulphur are also a popular albeit stinky treat. And should some blackened bun get stuck in your teeth as it did with mine? Think of ohaguro, the Japanese custom of blackening one's teeth common up until the end of the Meiji Period, and still practiced by maiko, or trainee geisha.

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