In Japan you can buy Kit Kat in watermelon, soy sauce, wasabi, matcha tea, cherry blossom or roasted chestnuts flavors.
The humble Kit Kat, a four-fingered wafer biscuit covered in milk chocolate, started out life in 1935 produced from Rowntree's factory in the English city of York.
The name came from a 17th century pastry chef, Christopher Catling, who hosted a literary club which became known as the Kit Kat. During the Second World War, with a shortage of milk, they had to switch to dark chocolate. But it returned to the original recipe in 1949 and was exported to Canada, Australia, New Zealand and South Africa and later to Germany and the United States.
Kit Kats only arrived on the shelves in Japan in the 1970s after a deal was struck with local confectionery company Fujiya.
The name struck a chord with the Japanese because it sounded like "kitto katsu", which means "sure win" in Japanese.
Over the years they have become a popular gift for Japanese youngsters preparing to sit exams.
Special gift packages are decorated with phrases like "Do Your Best!" and "Believe in Yourself!"
The first Kit Kat factory in Japan, at Kasumigaura, was built in 1989.
But this week Nestlé — who took over Rowntree in 1988 and later bought out Fujiya — announced plans for a second factory, at Himeji, to cope with demand.
Kit Kat accounts for 3.4 percent of the huge Japanese confectionery market. Japanese consumers, not content with the milk chocolate, dark chocolate and mint flavors available in Europe, have demanded wasabi, sake and purple yam flavors.
Many of those buying these exotic flavors are said to be tourists from Europe and other parts of Asia.
Spending by visitors on confectionery has more than tripled in the past four years to $1.2 billion, according to Japanese government figures.
A Kit Kat Chocolatory near the central station in Tokyo sells seasonal flavors including raspberry and grapefruit for as much as 3,500 yen (US$31) a box, 30 times the price of an ordinary Kit Kat.
"We have Kit Kat back in Germany, but it's not the same. The cultural touch makes it interesting. I bought a few packs of the wasabi ones, and I can't wait to shock my friends," said backpacker Matt Borscak.