As the Chinese and Sabah Native offspring, Sino is the only mixed ethnicity in Malaysia with Bumiputera status. Sabah Chinese refer to Sino as "Ban Tang Fan" ( half Chinese and half Native, in Hakka), and the name reveals certain exclusiveness from Chinese and Native perspectives. However, the variegated naming system of Sino provides some room for negotiation. In the naming system, the Chinese surname is the crucial Chinese (Tang) element. When the authorities have limited Sino' s rights since the 1980s, many Sino have discarded their Chinese surnames to preserve their Bumiputera rights ( known as "Buang Siang" locally). Buang Siang people subsequently changed their legal ethnicity to the Native, reflecting the fluidity of cultural identity. In the author's opinion, the Chinese pronunciation and the Chinese patrilineal system are not the primary reasons for the Chinese surname becoming the decisive ethnic boundary marker. Based on the historical changes of the naming systems of Kadazan and Tatana, who also have Chinese ancestry, the author argues that the critical factor is the weak affiliation of Chinese surnames with the places of residence. Chinese surnames could trace the family ties back to imperial China and the relative networks in China instead of Sabah. The naming system provides a membership to access Natives' resources, especially land resources. From the perspective of microscopic cognitive anthropology, the schemas of "pragmatism" and "ikut-ikut" ( to follow without much consideration) may affect the individual choice of Buang Siang or not. The former schema leads to Buang Siang, and the latter tends to preserve family traditions.