As mentioned in the introduction, long before the word Tsuchigumo was associated with being a type of yokai, it was a derogatory term used to demonize an ethnic group of people in Japan. While many scholars agree that the yokai was influenced heavily by these indigenous people, very little information can be found about the Tsuchigumo tribe. In a broad sense, Tsuchigumo was a term used to describe inhabitants that were beyond the reach of the emperor's control to rule Japan. Because they refused to serve the emperor, they were eliminated under the reign of the Yamato imperial court. In a way, the Tsuchigumo Tribe's narrative is very similar to that of Native Americans. Similarly to how the White Anglo-Saxon Americans wanted to conquer America, the Yamato Imperial Court wanted to rule Japan and when like Native Americans the Tsuchigumo people refused to bow down to their conquerors and conform, they were wiped out without legitimate reason (Kimura, 29). This may also explain why the Tsuchigumo Tribe remains such an allusive topic. Most information written about the Tsuchigumo Tribe is found in the ancient texts Nihonshoki and Kojiki which were both written from the Yamato Court's point of view. Even though our knowledge on the Tsuchigumo people is greatly reduced due to only having access to the conqueror's history, we can still a learn a lot about how these people were portrayed through the Nihonshoki and the Kojiki. Learning more about how the word Tsuchigumo emerged and the negative connotation surrounding this word will also help us understand the portrayal surrounding Tsuchigumo as a yokai.
Nihonshoki is one of the fist texts (Kojiki being the other) that uses Tsuchigumo as an ethnic slur. In Nihonshoki, Tsuchigumo translates to "earth-spider" and is first used in the text to describe a villian who dwelled in a pit. Later on, the Nihonshoki describes a tribe of people with short-bodies and long legs and arms who are said to live in pit-dwellings and once again they are referred to as Tsuchigumo. Thus the origin of the word Tsuchigumo is used to describe a group of people who choose to live unconventional lives rather than follow the cultural customs of Yamato Rule. The descriptions of the Tsuchigumo tribe in Nihonshoki may have also had influence on the yokai Tsuchigumo that first emerges in the popular Otogizoshi, Tsuchigumo-Zoshi. There is one story in the Nihonshoki that details the imperial army throwing woven dolichos nets to capture and murder defiant Tsuchigumo people (Reider, 60). However in Tsuchigumo-Zoshi, it is the Tsuchiguo that throws a net to catch its prey. This transformation from the Tsuchigumo being an innocent victim brutally killed, to a supernatural spider throwing silk threads to capture innocent prey is fascinating. In both stories, the Tsuchigumo is demonized and the story ends with the "earth spider" being killed by the "good guys". There is a great chance that the negative connotation of the derogatory term Tsuchigumo greatly influenced how Tsuchigumo as a yokai would be percieved, which in the case of Tsuchigumo-Zoshi is as a merciless demon-spider.
Tsuchigumo is once again used in Kojiki as a derogatory term to refer to indigenous people who defied imperial authority. In one specific story in Kojiki, Emperor Jinmu and his men come across a large number of indigenous pit-dwelling tribesmen described as "Earth Spiders" as he is on his Eastward expansion to claim his heavenly authority. The Earth Spiders end up being killed in bloody battles by Emperor Jinmu's men, though some survive after they apologize profusely for resisting imperial authority (Keegan, 9).
The Tsuchigumo people once again make an appearance in ancient Japanese text in Fudoki of Hizen. One story within the Fudoki tells of Emperor Keiko's imperial visit to Shiki Island and his discovery that Tsuchigumo are living on the island. After he orders the tsuchigumo people to be captured and killed, they beg to be forgiven by lowering their foreheads to the ground and pleading "we will from now on make offerings to the emperor" (Kimura, 29).
While over time Tsuchigumo became less associated with indigenous tribes and transformed from a derogatory term to a mythological monster, I still feel that the use of Tsuchigumo as an ethnic slur greatly influenced the portrayal of the Tsuchigumo as a yokai. In both cases, Tsuchigumo are unnatural, living in liminal spaces (underground pits, caves, mountains) and not conforming to societal standards. They represent the unknown and are shown as scary and evil due to their unconventional abilities. Similarly to how Tsuchigumo people are killed by emperors in various ancient texts, the Tsuchigumo yokai is killed by the great warrior Raiko in mythological texts and folktales. In both cases, the Tsuchigumo defy normal Japanese customs and are killed by heroic figures. Whether as a tribe or a gigantic spider-demon, the Tsuchigumo refuse to conform to Japan's societal standards and therefore must be eliminated.