In 1800, Atsutane came under notice of Tobei HIRATA (Atsuyasu HIRATA), who was a Soko YAMAGA strategist of feudal retainer of Bicchu-Matsuyama Domain and lived in Edo for generations, in hatago (inn with meals), where he was working at age of 25 and became his adopted son.
1800年（寛政12年）25歳の折に勤め先の旅籠で備中松山藩藩士代々江戸在住の山鹿素行兵学者であった平田藤兵衛（平田篤穏（あつやす））の目にとまり養子となる。