The variety of KitKat in Japan is so famous that many people including us almost forget that Kit Kat is a chocolate-covered wafer bar confection created by Rowntree's of York, United Kingdom, and is now produced globally by Nestlé, with the exception of the United States under a division of The Hershey Company.
The standard bars consist of two or four fingers composed of three layers of wafer, separated and covered by an outer layer of chocolate. Each finger can be snapped from the bar separately. There are many different flavors of Kit Kat globally but mainly in Japan. According to different sources, since 2000, Kit Kat has been produced with over 200-300 flavors in Japan, including ginger ale, soy sauce, creme brulee, green tea, sake, banana, wasabi, adzuki (red bean), purple sweet potato, brown sugar syrup, so on and on.
The flavors are designed to appeal younger buyers. Kit Kat also sounds similar to Japanese phrase "Kitto Katsu", roughly means "surely win." so the company has been marketing the candy as a popular gift to represent good luck to families or friends.
Start with Macha flavor and explore more (amazon link)