The basic purpose of this report is to investigate the chemical compositions of ancient glasses found in Japan,and to compare the chemical compositions with those found in China and Korea.From the ca 2nd century B C. to the 3rd century AD. distinctive glass systems were K_2O-SiO_2, PbO-BaO-SiO_2 and PbO-SiO_2 After the late 3rd century A.D. two systems of soda-lime glasses(Na_2O-CaO-SiO_2,Na_2O-Al_2O_3-CaO-SiO_2) appeared and above two systems of lead glasses disappeared, but after the late 6th century, PbO-SiO_2 system appeared again, and at the end of the 7th century this type of glass was produced in Japan for the first time.
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