This chapter also contains a direct reference to the Yamada Asaemon clan of executioners who worked for the Tokugawa Shogunate in Edo. The clan was believed to have had a side job making tuberculosis medicine using the powdered livers of the people they executed. This is the same Yamada Asaemon clan in Jigokuraku. This is the second time I've seen their liver-medicine side job mentioned in manga. The first one was the character Yamada Asaemon Yoshihiro from Blade of the Immortal.