It is an ume soda Kit kat - Ume is the pickled plum very popular in Japan and it has a strong salty-sweet taste - it appears the outside white chocolate of this bar is at first a plum flavour, then the fizzyness of soda hits your mouth - interesting...
Then there is ... Sports drink flavoured Kit kat
Perhaps so you can have a both a chocolate and energy hit in one go!
And just to show that chocolate bars can be healthy - Kit Kat created vegetable flavoured Kit Kat bars
This Kit Kat is said to contain apple, carrot, grape, lemon, celery, green pepper, asparagus, Chinese cabbage, kale, and herbs. It smells and tastes like apple with an undertone of carrot.
Kit Kat Japan often bring out special flavours for each season - here are some more:
Soy sauce flavour
Blood orange flavour
Chestnut flavour
Pineapple flavour
Mc Flurry flavour
Red bean soup flavour
apple flavour
Espresso flavour
Green tea flavour
Pumpkin flavour
Toasted soy flour flavour
Caramel and salt flavour
Potato flavour
Watermelon and salt flavour
Toasted corn flavour
Apple vinegar flavour
And finally Candied sweet potato flavour