The Taiwan Dog (Chinese: 台灣犬) is a breed of small or medium dog indigenous to Taiwan. These dogs are also known as the Formosan Mountain Dog, Taiwanese Canis, Taiwanese Native Dog (台灣土狗) or Takasago Dog (高砂犬). Sung Yung-yi that have been critical in the development of the Formosan Mountain Dog: the Dutch settlement of Formosa, the Japanese rule, World War II and the Kuomintang Era. The Formosan Mountain Dog was originally kept by Taiwanese aborigines as hunting dogs, but now purebred Formosans are extremely rare and valuable. Nevertheless, this breed is now popular all across the island as a watchdog and companion dog.