In the third year of the Keio era, the year before the Meiji Restoration, a pilgrim visited a merchant's shop in Uwamachi and asked for a place to stay for the night. The merchant's house is said to have given the traveler great hospitality. In return, the pilgrim taught the merchant how to make manju.

The deliciousness of the manju soon gained a reputation, and the owner believed that Yamada Yakushi, a deity whom he devoutly worshipped, had appeared to him in disguise to teach him the secret. With this belief, he opened a shop under the name "Yamadaya" that same year. It is said that this became the "Yamadaya Manju" known today. (Note: 'Manju' is a traditional Japanese confection made of sweet filling wrapped in a dough.)

The recipe invented by the founder, Genzo Takatsuji, has been passed down as a secret through the second and third generations, and the fifth generation continues to carry on the taste. By steadfastly focusing on making just one type of manju—a traditional Japanese confection—the company has become beloved by many fans not only in its hometown of Ehime, but also throughout Japan and even overseas.