Since ancient times, the salt industry thrived in Kojima, in Kurashiki, Okayama Prefecture. It is recorded on a wooden strip of the Heijō Palace that salt was already being produced in the Nara period.

Larger salt farms developed in the Edo period. Nozaki Buzaemon from Kurashiki greatly contributed to the development of salt manufacturing at this time. Nozaki came to be called the 'salt magnate' and in 1833 he made a grand home for his family. The total area of the family residence is about 9900㎡ and includes several storehouses constructed around a main building.

In 1977, buildings such as Omote-shoin, Nagayamon and Onarimon were designated as important cultural assets of Okayama Prefecture. Tearooms are constructed here and there in the garden, adding various ways to view the four seasons. The storehouse is now used to display a history of the salt industry and includes records of salt farming with tools and clothing that were actually used by the Nozaki family.

The Kumagai family were influential and important merchants during the second half of the Edo period (early 19th century). Their old residence is in the town of Omori, Ota-shi, Shimane Prefecture. In those days, the residence was also used to receive officers of the daimyo (feudal lords) and junkenshi (ambassador/inspectors from the Shogun).

Because of severe deterioration of the house, it has been undergoing some renovation since December 2001.

The Kumagaike Family Residence has been designated an Important Cultural Property of Japan and is the largest existing residence of a wealthy merchant within a preserved residential area. The total area of the residence is about 1,500m2. The main building is a two-story wooden house of 30 rooms, with an area totaling about 265m2 (160 jyo). Within the compound, there are five warehouses for storing rice and other miscellany.

The building itself is astonishing, with elaborate interior decorations, such as 'fusuma' (sliding doors) with a cloud design called 'kumo-tatewaki-monyou'; and 'yoshido' (matchstick blinds), which let in cool, comfortable breezes in summer.

Around 3,300 articles have been donated to Ota-shi from Kumagaike. Many ancient pieces of literature have also been found on site and are being examined and analyzed.

Currently, the house is exhibiting many articles, which were actually used during that time, and which show the actual lifestyles of people at that time.