The Duqa or Tuxsi (Chinese: 獨孤; Kharakhanid: تُخسِى) were originally a Xuŋa tribe that defected to the Särbi. They played an important role in the politics of Inner Asia. One of their descendants would come to establish the Tang Dynasty (唐朝).
The clan is recorded in Chinese records as the Du-gu (獨孤) LH *dok-kuɑ. They would change their name to Liu (劉) “battle axe” during the Northern Wei Dynasty. While Liu is likely referring to the Liu name of the Han Dynasty, it is possible that it was chosen for its semantic meaning of “battle axe.”
The Du-gu clan, for instance, was not limited to the Xuŋa or Särbi. It so happens that it had a far eastern branch in Korea, known as the Namwon Dokgo clan (남원 독고씨). Furthermore, the Korean word for an axe or hatchet is dokki (도끼) /ˈto̞(ː)k͈i/, itself from Middle Korean *doskui (돗〯귀〮) *tu(ː)sk[ü]j. The Middle Korean word, itself, is likely related to, if not derived from Mongolic *togsi “to hit, strike, beat.” In turn, the Mongolic word is likely the root for the tribal name of the Tuxsi (تُخسِى) tribe of Turks. Finally, the Tuxsi could then be a branch of the Du-gu, whose original name would be Duqa, from Turkic *tokɨ “to hit, strike; mallet, hammer.”
An interesting parallel may exist in the name of Doqaq (دوقاق), the father of the eponymous Sälçük Bäg. Doqaq, whose name likely meant “hammer,” was the son of either a well-known blacksmith or yurt maker.