Mortar ball - Usudama

A type of bead from the Kofun period. Shaped like a short slice of bamboo, it is about 5 mm in diameter and 2 to 3 mm thick, with the diameter being larger than the thickness. The outside is straight, but some have bulges and are often crude products with unevenness on both the top and bottom. There are rare examples made of jasper or glass that are thought to have been used for jewelry, but generally they are made of talc and are often excavated in large quantities as a group for use in rituals. Note that from the Stone Age, there were crude round beads in the shape of mortar beads.

[Murai Takeo]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

古墳時代の玉の一種。竹管を短く輪切りにしたような形で、直径5ミリメートル、厚さ2～3ミリメートル程度で、厚さより径が大きい。外側は直をなすが、なかには膨らみをもつものもあり、上下両面に凹凸があるなど、粗製品が多い。碧玉(へきぎょく)岩やガラス製で装身用とみられるものもまれにあるが、一般に滑石(かっせき)製で祭祀(さいし)用として一括し大量に出土する例が多い。なお、石器時代には丸玉の粗製品のうちに臼玉形をしたものがある。

［村井嵓雄］

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