Oike family was one of the major merchants who obtained great wealth in the vicinity of Naka-machi which played a central role for commercial development in Niimi. The family’s house was built around 1900 （at the late Meiji-era), the family owned and operated a department store dealing with a variety of goods including KIMONO fabric. Currently, the residence is on loan to Niimi city and is used as community facility.

A lord of Seki named this street Jufuku-Matsubara. Jufuku was derived from Jufuku-in, the posthumous Buddhist name of Nagamasa Seki （han founder). The street name, Matsubara, is still used though the withered 200 years old pine trees, matsu, were cut down in 1940 （Shouwa 15). The tenth lord, Hironao, wrote the “Jufuku Matsubara Document” that is preserved as a treasure at Seirai-ji Temple

This area used to be the Takahashi River until the Lord Nagaharu Seki developed Niimi town. The side ditches behind the fire-extinguisher storage are the remains of the river flow. The town, planned by Lord Nagaharu, changed the river flow. For example, the vicinity of present day Matsubara Street is reclaimed land.

It is said that Watanabe family was an accountant for the lord, who dealt with local merchants. In the front yard, there used to be a Japanese white pine tree which was a gift from Masamune Date; there is a gate building in front of the residence. Currently, Onkokan is owned by the city and open to the public.

During Edo period, a shiken-haba （7.2 meter-wide) street was forbidden to be built by han’s with less than 50,000 koku. It has been a big mystery that Niimi han, with only 18,000 koku, was able to build such a wide street after load Seki moved from Tsuyama to Niimi. “Niimi-ki” was written by a Confucian doctor, Yugen Hachiya, who described the origin of Niimi town’s people including Seki clan. In his book, he wrote the phrase that “name and reality coincide”. It was then realized with information about Seki family that was treated as though it had a lord with 50,000 koku and more. This was possibly because the wife of Nagaharu Seki was a daughter of Naruse-Hayato-shouke, the lord Inuyama and a minister of Owari-Tokugawa Family, and because she was also related to Tokugawa Family.

Shiseikan is the third oldest han school established in Okayama prefecture, built in 1755 （Houreki 5) by the third lord of the Niimi han, Masatomi Seki. The school’s name “Shisei” means “sincerity” and was derived from Mencius prose, “Sincerity is the way of heaven, practising sincerity is the way of life, there is none that does not move with sincerity.”

95 years after Shouin Marukawa died, he was posthumously elevated to Junior 5th Court Rank by the government. In commemorating this award, a monument of honor was erected by “Shouin-Kai”, local volunteer group in 1929 （Showa 4), when the railway construction was completed to Niimi. The epitaph was made by Fumimaro Konoe and the inscription was by Issai Sato.

The monument of the Niimi han palace is located where its main entrance used be. The palace buildings themselves were located on the current school grounds. The inscription of the monument was written by Tsuyoshi Inukai, a former prime minister, and the epitaph by the tenth Niimi lord, Hironao. Both of them had a close relationship in the House of Peers, Kizokuin.

There were two river ports in Niimi, one in the rear side of Hon-machi and another at Mikkaichi, behind Shinpuku-ji Temple. The stone walls of the banks were constructed 350 years ago using a special technique called Mizunoyamaki, and still have not been badly worn to this day. In order to control the water flow when loading or unloading, a weir was built; it is called Mikkaichi Kerrepu (Krippen Groin). At these river ports, most of iron and other products were shipped between Niimi Domain including shogunal demesne of the Northern Bitchu and Matsuyama Domain. Takasebune boats left Niimi for Takahashi at eight o’clock in the morning, stayed overnight at Takahashi port, and returned to Niimi on the following day. The frequency of the service was six times a month: 3rd, 8th, 13th, 18th, 23rd and 28th day. Some boats made a return trip to Tamashima in a week. The fee was about 3000 to 4000 yen at present day values.

Mint bureau, Iron Wholesaler, and Sake Brewery in the Edo period, Tsunokuniya’s Uchikura was built in 1814 (Bunka 11) exactly when Houkoku Yamada was studying at the home-school under Shouin Marukawa. Inside the Uchikura are displayed a Shinto alter, that has the width of 2.7 m, with seven different Gods, a gargoyle (roof-ornament) of sake brewery, a letter from Houkoku Yamada, and other household items. Townhouses