The text of "Hokuetsuseppu"by Bokushi SUZUKI is referenced in the description of Ojiya, Echigo Province and there is a scene of ushi no tsunotsuki (bullfighting) which actually takes place there.
越後小千谷の描写には鈴木牧之『北越雪譜』の原稿が参照されており、同地で行われる牛の角突きが作中に取り込まれている。