This article focuses on the people who supported the Korean embassy missions in Tokugawa Japan and examines the Chosenjin Goyo in Tonami, Etchu Province, in Kyōhō 4 (1719). As is well known, the embassies represented formal diplomatic missions dispatched by the king of Choson to the Tokugawa shogun on the premise of promoting diplomacy between equals based on the good-neighborly relations between Japan and Choson. Even under the “seclusion” (sakoku) policy, the arrival of the embassy missions in Japan was not only a solemn diplomatic ritual but also a state ceremony that demonstrated the legitimacy of the new shogun both in Japan and abroad. For this reason, the Tokugawa Bakufu established a state-level system for receiving and escorting the embassies on their journey to Edo. On the other hand, the Kaetsuno region (Kaga, Noto, and Etchu), held by the Maeda family of the Kaga Domain, lay outside the embassy route and had long been considered an area unrelated to the embassies. Recent research, however, has shown that the Kaga Domain undertook the joma-yaku in years when the embassies came to Japan, and that villages in the Kaetsunō region were mobilized for Chōsenjin Goyo. In this article, focusing on the case of Kyōhō 4 as recorded in the Chosenjin Goyo Uma Tomechō (Register of Horses for Chosenjin Goyo) in the Kawai Documents, preparations made by Tomura officials, including Kawai Mataemon of Toide Village, Tonami, Etchu Province, for the dispatch of post horses, horse drivers, and horse supervisors are analyzed. In the home territory, post horses suitable for official service were selected through horse inspections conducted by the Osanyoba, the domain accounting office. Specifically, 15 official-service horses were dispatched from Nakada, Hanyu, and Sagano villages under the district administration, and from Imaisurugi-machi under the town administration. Even after the horse inspection, the local Tomura officials made painstaking arrangements: they replaced horses suffering from eye disease and bore the cost of outfitting the horse supervisors and their retainers. The actual service of joining the embassy procession between Maisaka and Edo lasted only nine days. Even so, preparations for dispatch took four months, showing the thoroughness with which the Kaga Domain authorities back in the domain engaged with the task. Maeda Tsunanori, then lord of Kaga Domain, went to view the procession when the embassy entered Edo, watching over the contingent from Kaga as it carried out its task. Later, after returning to the home territory, the horse supervisors recorded the scenes of the procession that they had witnessed firsthand in a document entitled Chosenjin Nori Gyoretsu No Oboe (Memorandum on the Korean Procession on Horseback). The Tomura officials, too, compiled details of the official service in the Chōsenjin Goyo Uma Tomechō and transmitted it to posterity with their own hands. The Chosenjin Goyo (dispatch of post horses), which derived from the jōma-yaku of the Maeda family, in the Kaga Domain, was clearly carried out by the horse supervisors and horse drivers of the villages in the Kaetsunō region, as well as by the Tomura officials, who did not themselves travel to the site. Thus, it is an undeniable fact that the embassies were supported in their missions not only by persons connected with the Tokugawa Bakufu and Tsushima Domain, but also by large numbers of Japanese people gathered from distant regions to the route of passage. Further attention should be given to the fact that their earnest efforts made the embassies’ journeys to Edo possible and sustained the good relations between Japan and Choson.