Public domain
Explanation of the Four Tones, 2 Volumes
From the collection of National Diet Library, Japan. Free to download, adapt and use — no permission needed.
Subjects
Credit line四聲通解 2卷. 正徳12 [1517] 序. (朝鮮) 崔世珍 奉教抄編. National Diet Library, Japan. Public domain.