Tokyo, Feb. 2: The makers of Kit Kat are struggling to cope with a surge in demand for the chocolate bar in Japan, because the country?s teenagers believe it will help them pass exams.

Kit Kat, an expression invented in Britain in the 1930s, sounds eerily close to ?kitto katsu,? a Japanese exam-season mantra that literally means ?I?ll do my best to make sure I succeed?.

The quirk of language has provoked a run on the snack.

Tens of thousands of students? lunch boxes will contain the bar this month, put there either by ambitious parents anxious for their offspring?s success or by the nervous children themselves.

Nestl? Japan has noticed previous surges in sales of the product, which is Britain?s most popular chocolate bar. This year it has made an extra effort to sweeten the tough process of getting into a Japanese university.

And to appeal to more Japanese youngsters ? who are notoriously keen on sweet foods ? the company has introduced a range of flavours.

As well as the traditional red-and-white packaging of the familiar four-fingered bar, Japan?s Kit Kats also come in lemon cheesecake, passion fruit, white chocolate and even green chocolate flavour.

In the past, students preparing to sit for the dreaded ?juken? entrance examinations for both high school and university would be served ?katsudon? ? breaded pork cutlets served over rice ? as a good luck meal before the big day. But as with much else in Japanese culture, this homegrown tradition has been forced to make way for a western import.

?We?re finding that parents are buying them for their children for exam days, but also some determined pupils are buying Kit Kats for themselves as a sort of reminder that they are really going to give these exams their best shot,? said Yuko Iwasaki, a spokesperson for Nestl? Japan.