Kidō Okamoto: 14 works in the original Japanese, with translation

A low-ranking samurai post in the Edo shogunate. Foot soldiers (kachi) were samurai who served the shogun on foot, as opposed to samurai who travelled on horseback. Members of the otachi-gumi served as guards on foot and performed miscellaneous duties when the shogun travelled, and were mostly filled by men of low rank.

The Russo-Japanese War ended with the Treaty of Portsmouth in September 1905. The story takes place shortly afterwards. Since, as mentioned below, the elder brother was wounded at the Battle of Mukden and had already gone to Yugawara to recuperate in February, this must be around 1906, in the final years of the Meiji period.

Refers to the Great Kantō Earthquake, which struck the Tokyo and Yokohama area on 1 September 1923 (the twelfth year of Taishō), killing or injuring over a hundred thousand people and burning down large parts of Tokyo; it was customarily called "the earthquake disaster" (shinsai) at the time. The narrator was in Takayama, far from the disaster zone, and with communications cut off the details were at first unknown, hence the descriptions of the whole town in turmoil and people asking around for news.

An abbreviation combining Yun Prefecture and Shuo Prefecture, referring collectively to the bitterly cold frontier regions of northern China. The author uses this elegant Chinese term to evoke the bleak desolation of the Manchurian countryside.