Cereal

Unfortunately, when it comes to cereal, we have such a poor selection of it. Why? Well, first of all, cereal is not a widely loved breakfast food in Japan -- we usually prefer toast or rice. Although it is getting popular, still regular supermarkets don't sell many unlike western countries where they have a whole aisle of cereal. 

Kellogg's seems to be the most famous cereal company in Japan as it is possibly the only company you would be familiar with here. Regarding Japanese brands, Calbee is the biggest. Also, there are some store brands.

What you may find at a regular supermarket:

Normal

・Kellogg's Corn Flakes (sugar free)

・Kellogg's  Frosted Corn Flakes

・Kellogg's Honey Nuts Crunch

・Kellogg's Chocowa

・Kellogg's Choco Crispy

・Kellogg's Pooh-san no Hachimitsu Daisuki

・Calbee Corn Flakes (Normal, Brown Sugar and Chocolate type available)

・Calbee Choco Puffy

Granola

・Kellogg's Granola  (Fruits and Chocolate types available)

・Calbee Fruit Granola
 

Diet
・Kellogg's Genmai Flakes
・Kellogg's All-Bran
・Kellogg's All-Bran Flakes (Normal and Fruits-mix)
・Kellogg's Special K (Red Berries)


Also, there are bar and sandwich type cereal.
Ex: Asahi BALANCEUP series
       Kellogg's Special K series