In our first episode, we dig up the origins of  the Back: the land of Koshi, which includes modern-day Niigata, Fukui and Toyama prefectures. We find references in the the Kojiki (712 AD) the Nihon Shoki (720 AD) and the Izumo no Kuni Fudoki (733 AD). Also, big unpronounceable names abound:

Izanakino-no-mikoto - primordial male deity associated with Japan's creation story 

Izanamino-no-mikoto - primordial female deity associated with Japan's creation story 

Ōkuninushi (Yachihoko-no-Kami) - the god of agriculture and champion of t Yamata no Orochi

Princess Nunakawahime -  goddess of jade from Koshi, modern-day Niigata prefecture 

Yatsukamizu Omizunu (Omizunu) - relative of Susano-o, latter ruler of Izumo

REFERENCES:

Kunibiki Myth: https://www-pref-shimane-lg-jp.translate.goog/life/bunka/bunkazai/izumo_fuudo/kunibiki/fudo03.html?_x_tr_sl=ja&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=sc

Princess Nunakawahime: https://rekishi--shizitsu-jp.translate.goog/nunakawahime/?_x_tr_sl=ja&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=sc