According to a very unscientific study, Ranking TV, interviewing 200 girls in Shibuya, Hot Cocoa is the #1 hot drink in Japan. Much stranger, #2 was Corn Soup!! Yes, 47 people out of 200 picked Corn Soup as their favorite hot drink. This over other things like, Milk Tea, Cappuccino, Cafe' Ole, Oolong Tea.
If you were wondering, you can buy all these drinks in cans nice and hot from vending machines. Sometimes when it's really cold people buy one just to hold the can and warm themselves with it