After World War II, high-quality chocolate was sold by weight, broken into pieces, and became a popular item in department stores. This type of chocolate was called " Kachiwari chocolate" or "block chocolate".
The "b" sound in "block chocolate" was removed, leading to the name "Rock Confectionery".

In 1928, Momoichi Yoshimura founded a confectionery manufacturing and sales business in Kanda, Tokyo. After the war, in 1948, he rebuilt the business at the same location and began manufacturing chocolate.
By 1953, we launched Coin Chocolate (a registered trademark) amidst a time when rising prices led to the production of chocolates made with inexpensive materials. However, we remained committed to making pure chocolate, driven by the belief in ‘providing real chocolate to Japanese children.’ This spirit endures to this day.
At our Yachiyo factory, we create our original chocolate by carefully blending raw materials.
We use granite during the manufacturing process—a method shared by only two companies worldwide—and traditional conching machines to refine the chocolate, resulting in a product with reduced metallic flavor. (*1) Our mission is to offer safe and reliable confectionery tailored to each customer’s needs with high quality and flexibility, bringing smiles through our treats.
We aim to continue crafting delicious, beautiful confections enjoyed by families, co-workers, and friends.

(*1) During the conching process, excess moisture and odors are removed, creating a smooth, chocolate-like texture.