This is HAPPYTURN ハッピーターン and a popular Japanese snack which is a kind of rice cracker.
It is really good to eat.
I think that once you start eating them you won’t be able to stop eating until you finish the package which holds about 30 crackers. (120g)
They are sprinkled with special powder which tastes sweet, salty, sour and has some other good flavors.
The taste of the powder is so enjoyable you just keep eating.
You can get HAPPYTURN ハッピーターン at many supermarkets and convenience stores in Japan. It costs about 180 yen.
While traveling in Japan, you should try eating them.
Official website (in Japanese)