was an Edo period Japanese samurai, and the 8th daimyà  of Nihonmatsu Domain in the Tà Âhoku region of Japan. He was the 11th hereditary chieftain of the Niwa clan. His courtesy title was Saikyà Â-no-daifu, and his Court rank was Junior Fourth Rank, Lower Grade.
Nagaakira, first known by his childhood name of Nabetarà  (éÂÂ太éÂÂ), was the eldest son of Niwa Nagayoshi by a concubine. On June 17, 1796, he became daimyà  upon death of his father. His fundamental approach from the time of his succession onwards was that of restructuring the domain's finances. Relying on his reformist karà  Narita Yoriyasu (æÂÂç°頼ç¶Â), he encouraged agriculture, promoted education, and assisted in the development of special crafts amongst the commoners. It was at this point that Nihonmatsu's famed Banko-yaki (äºÂæ¾¾ä¸Âå¤ç¼) glazed pottery, Kawasaki paper (å·Âå´Âã®ç´Â), Hiraishi tatami (å¹³ç³ã®ç³), and à Âhira kushikaki (大平串æ¿; skewered persimmons) were originated. Nagaaki also encouraged sericulture and established horse and silk markets in Nihonmatsu.
Despite these reforms, the domain's finances were hard pressed due to natural disasters and other unforeseen events, as well as the shogunate's request for monetary and construction assistance on flood control projects.
Nagaakira died in 1813, and was succeeded by his eldest son Niwa Nagatomi.