This is due to the following reason: Towards the end of the 17th century, ten guilds called Edo tokumidonya, each for a different kind of business, were established, and in particular, many merchants from the Mikawa Province, who had supplied goods to the Matsudaira family since the era when Ieyasu TOKUGAWA was the daimyo (feudal lord) of the small Mikawa Province (or who said they were such persons), belonged to the 'sake store guild,' which handled sake, miso (fermented soybean paste) and soy sauce, and were prosperous.
これは、17世紀末には江戸十組問屋という10の同業者組合ができ、中でも酒、味噌、醤油を扱う「酒店組」には、徳川家康が三河を領していた小大名だったころから松平家に出入りしていた（あるいは、そのように自称する）三河出身者が多くまた繁盛したことによる。