Takemoto 【嵩元】3 The Japanese surnames etymology dictionary.
① There is a 当麻 surname. Okayama-ken Okayama-shi Hirayama is Kita-ku. Okayama-ken Okayama-shi Kita Ward Marunouchi was in the Edo period in the Okayama Samurai of the Clan Office, Okayama-ken Kurashiki-shi Fujito Machimokechi.
② things . In Ishikawa-ken , say that you added "horse" by horse you kept because there was a mistake of letters in the Tokyo era with East (Azma) surname and East (Higashi) surname. The pronunciation is Azuma. 東 reference.