Thread mark - Itoin

A copper seal was affixed to each jin (600 grams) of raw silk imported from the Ming dynasty. During the Muromachi period, Japan imported a large amount of raw silk from China through trade between Japan and the Ming dynasty. One seal was affixed to each jin (600 grams) of imported raw silk. After the shipment arrived, the weight was inspected, and if it was received without any abnormalities, the seal was stamped on the receipt and returned to the sender. The seal was not returned to the recipient, but left with the recipient. These seals were cast copper seals and always had a knob, which could be in the shape of a dragon, lion, dog, monkey, or other animal or human figure. The shape of the seal surface also varied, from circular to square, and the inscription varied from legible to simply pictorial.

Although they were not elaborate, many of them were full of elegance, and so they were used as objects of entertainment for connoisseurs in later times. As for the ones used by famous people, it is said that Toyotomi Hideyoshi used a circular seal for his seal letters as an ito-in.

[Masuo Murai]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

明(みん)からの輸入生糸(きいと)1斤(きん)ごとに付した銅印。室町時代、日明貿易によってわが国は中国から多量の生糸を輸入したが、輸入生糸には1斤（600グラム）につき1個の印を添付してあり、荷物到着後、斤量を検査し、異状なく受領したときは受領証にこの印を押捺(おうなつ)して荷主に返送した。このとき印章は先方に返さず荷受人の手元に残した。これらの印は鋳銅印でかならず鈕(ちゅう)があり、鈕には竜、獅子(しし)などのほか、犬、猿などの動物や人物などさまざまの形のものがある。印面の形態も円形、方形など各種のものがあり、印文も文字の判読できるもの、単なる図形状のものなどさまざまである。

　精巧なものではないが雅趣に富むものが多かったので、後世好事家の愛玩(あいがん)用として利用された。著名人の使用したものとしては、豊臣(とよとみ)秀吉が印判状に使用した円形印がこの糸印であるとされている。

［村井益男］

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