A fragment of the mold dated around the year 200, was found during an archaeological excavation at the Sugu Takauta ruins in Kasuga. The mold appears to have been used for produce bronze mirrors known as Tachukyo, during the first half of the Yayoi Pottery Culture (300 BC-300 AD).
This discovery rejects the thesis that this type of mirrors were imported from the Korean Peninsula and suggests that mirror production is more recent than previously thought in Japan.
Until now, it was believed that the first mirrors produced in Japan were those of Kogata Boseikyo, which were imitations of Chinese mirrors, but the mold that has been found dates the mirror 150 or 200 years than previously thought.
The fragment has the following measurements: 5.1 centimeters in length and 2.5 centimeters in width and 2.3 centimeters in thickness and weighs 39 grams.
The Sugu Takauta ruins are located in the central area of Nakoku, a kingdom within Japan