Nushizumi YAMAJI became the assistant of Noriyoshi SHIBUKAWA and Masayoshi NISHIKAWA at the time of Horyaku calendar revision (Horyaku Calendar), and he was appointed to Tenmonkata in 1764.
山路主住が宝暦の改暦（宝暦暦）の際に渋川則休と西川正休の補暦御用手伝となり、明和元年（1764年）に天文方に任命されたのに始まる。