Shimazaki Masaki (島崎 正樹; 1834–1886) was a Japanese gōnō, honjin master, student of kokugaku, and Shinto priest. He was the father of Shimazaki Tōson. He primarily wrote under the name of Aratamanoya (璞堂),^[1] but later in life also adopted the names Shizunoya (静舎; transl. "house of serenity") and finally Kanzanrō (観山楼). His courtesy name was Sachio (禎夫), and he was referred to by relatives as Kichizaemon (吉左衛門), the family's hereditary name.

Shimazaki Masaki was born under the apotropaic name Kanatarō to Shimazaki Kichizaemon Shigeaki (島崎 吉左衛門 重韶), hereditary chief of the Magome relay station in the Kiso Valley. The young Masaki taught himself to read and write with great difficulty using the few books available in the village, often outdated and poorly copied manuscripts, in both Japanese and Classical Chinese.

After an introduction by Hazama Hidenori of Nakatsugawa, Masaki became an exceptionally dedicated disciple of the nativist Shintō theology of Motoori Norinaga and Hirata Atsutane under the tutelage of Majima Sei'an, a student of the samurai-scholar Aoyama Kagemichi of Naegi Domain, the first Hirata disciple in the region. The theory of Hirata Atsutane, a fundamentalist, that the importation of foreign ideas like Buddhism in ancient times had corrupted a pristine, theocratic Japanese nation powerfully influenced Masaki for the rest of his life. Alongside the other Hirata disciples of Mino and Naegi, Masaki was involved in the promotion of traditional Shintō funeral practices in opposition to the officially mandated Buddhist alternative. During this time he also became acquainted with Matsuo Taseko [ja] and Tsunoda Tadayuki.

In 1864, after having assumed leadership of the station from his father, the Tengutō passed through Magome. A poem left by Kameyama Yoshiharu at this time later came into Masaki's possession. Though he wanted to travel to Kyoto to assist the other Hirata disciples in their agitation there, he stayed in Magome due to a sense of responsibility to his family and the people of the village. He remained in Magome throughout the Boshin War, and on more than one occasion arranged lodging for the revolutionary Imperial Army.

In 1874, having retired and passed financial authority to his eldest son, he travelled to Tokyo and secured employment within the Historiography Division (考証課) of the Department of Religion (教部省), the temporary successor to the older Department of Divinities. However, he soon left disillusioned with his coworkers flippant attitude toward and lack of dedication to Shinto. That same year, he inscribed a poem on a folding hand fan in which he expressed his fear that Japan's cultural values and national identity would be either forgotten or discarded by a cosmopolitan population with an uncritical admiration for Western culture:

If the crab's burrowing is not stopped, the high levee will not last long
蟹の穴ふせぎとめずは高堤やがてくゆべき時なからめや

At the time of a public cavalcade by the Emperor Meiji, Masaki threw the fan into what he believed to be the carriage of the emperor's outriders in the hope that the message would come to the emperor's attention. He was arrested immediately charged with the crime of impiety, but was not penalized beyond a minor fine due to the court's assessment of the motivations for his act. He later became aware that the fan had in fact landed in the carriage of the emperor himself.

In 1875, as part of the government's expulsion of Hirata influence, Masaki was rusticated by the Department of Religion to the remote Minashi Shrine to serve as a resident priest. He remained at Minashi for four years, and became known to locals for bursting into tears while conducting lectures on legendary national history. According to Shimazaki Tōson, it was during this time that Masaki came to greatly respect Tanaka Ōhide, the foremost kokugaku scholar of the Hida Mountains.