Seonggyun-gwan's (성균관, the national school in Goryeo and Joseon Dynasties) slaves, known as Ban-in (반인, 泮人), was regarded as the Bonsandae (본산대) mask play troupe and was also regarded as the butcher. This theory associates Ban-in with Su-cheok (수척, 水尺), a butcher originating from northern nomadic cultures, traditionally grouped under the umbrella of Gwangdae (광대) in the northern regions. The 'Ban-in' theory was already wrong from the beginning due to the fact that the Ban-in was not a Sandae-hui (산대희) player. Despite its questionable foundation, Jeon Gyeong-uk has steadfastly supported this “Ban-in” theory since 1997, bolstering it with publications like 'Su-cheok and Ban-in as Performers seen through new Materials' (2014) and recent works such as 'History of Korean Traditional Play” (2020), “Dictionary of Korean Traditional Play” (2014), and “Books of Korean Traditional Play” (8 volumes) (2020), with the aim of popularizing it, even among researchers in the field.
 In response, this paper seeks to broaden and reinforce the arguments put forth by Son Tae-do and Sa Jin-sil, who have opposed the “Ban-in” theory The theory suggests that Jeon Gyeong-uk's Seonggyun-gwan's slaves, Ban-in, is regarded as northern region Gwangdae group.
 He says that Chuyeop-ryong (추엽륭. 秋葉隆) was convinced that Ban-in served as the Bonsandae mask play troupe. He also contests the claim that Ban-in participated in the unique Sanbung-japhui performance during the 12th year of King Yeongjo's reign and that Ban-in was indeed the butcher. These contentions collectively refute the 'Ban-in' theory's validity.
 Furthermore, the additional materials Jeon Gyeong-uk introduced to support the “Ban-in” theory lack substantial evidence for its reinforcement. Previously, interpretations of texts such as 'Munjong-sillok' and 'Gyerimyusa' indicated that 'Su-cheok' referred to characters participating in Sohakjihui, while 'Gojak' denoted the offspring of clowns, rather than reinforcing the “Ban-in” theory. Hence, the notion that “Su-cheok,” the butcher, is synonymous with a clown or part of the northern Gwangdae group is no longer tenable.
 Conversely, the paper explores the presence of the Hwarangi group, Mubu, and the musicians, and clowns in the southern region, postulating that they may have made their way to Hwarang of Silla from distant places. In contrast, musicians and clowns belonging to the northern Jaein-chon came from Gisaeng's sons and became musicians and subsequently musicians and clowns during the middle of the Goryeo Dynasty, as evidenced by the historical record that “Gisaeng's sons become Akgong” in 'Gyerimyusa' (1103).
 Traditional society in Korea operated on a caste system, with specific roles assigned to individuals based on their caste. Understanding the history of traditional performing arts in Korea requires a comprehensive examination of the establishment of the Gwangdae group, the official entertainment group of traditional society. While the Hwarangi group, consisting of clowns in the southern region, was well-known in the past, research on the northern region's Jaein-chon, a group of clowns, only gained momentum following the investigations of Kim Yeong-taek (1920-2000) conducted by Son Tae-do and Lee Ja-gyun in 1998, based on the life of Kim Yeong-taek (1920-2000), a native of Jaein-chon. It was not until 2001 that the Jaein-chon men were formally recognized as a northern clown group.
 The 'Ban-in' theory has cast a shadow over the proper understanding of the northern Jaein-chon clown group. Thus, it remains imperative to debunk Jeon Gyeong-uk's erroneous theory of 'Ban-in' and to facilitate more accurate investigations and research into the Jaein-chon men, who were indeed a northern clown group.