Found the best japanese お菓子 (candy), finally ^^ It's called ひじり (hijiri) and are almost the same as mochi's, but flat and softer. They have different fillings, but my favorite is the matcha (green tea) and white ones with bean paste inside (= (first pic on the right). The traditional ones.
Natural with sakura filling and Natrual/Matcha with bean paste filling.
Natural with strawberry filling and Black with sesame filling.