He was the younger son of Nakai Shuan (1758 d.), one of the Kaitokudo's two founding leaders, and was influenced by his teacher and mentor Goi Ranju.
Often stated as analogous to his floating calligraphic style Riken was vastly different in demeanour to his brother Nakai Chikuzan, although their underlying epistemologies, beliefs and degree of tenacious individualism were similar.
They both furthered the work of Goi Ranju and consolidating previous thought around the Kaitokudo school, bringing a level of prestige to the academy.
However, his lasting legacy was in reaching a point of contradiction between the demand for verifiability in the Kaitokudo school and the reliance on the reading of text as history.
It is said that Chikuzan has ongoing and great influence on his thought, but that Riken was more heavily involved in the final push toward publication of Yamagata’s work yume no shiro .