Ritual bronze mirror. Japan early Edo period 17th century

A mirror made of white bronze, a Japanese alloy of copper with a high tin content (Hakudo), very hard and producing a clear ringing sound when struck. Beautiful silver color with golden highlights. Intricate high-relief decoration depicting symbols:
The tortoise, living 10,000 years: Longevity.
The two cranes, living 1,000 years: Longevity, happiness, and harmonious marriage.
The three friends—the pine, plum, and bamboo—representing steadfastness and virtue in the face of adversity.
A Paulownia (Kiri) flower: Imperial legitimacy, ensuring peace and prosperity.
The double circle certainly has symbolic meaning, which we have not yet deciphered, as does the joining of the three beaks, which is not always present on other tortoise-and-cranes designs.
A five-character signature, "Tenka ichi ise" (The best under the heavens of Ise). This "Tenka Ichi" mark, authorized by Nobunaga, was used on the most prestigious objects from the late 16th century, particularly during the Momoyama period around 1600. However, over the years, some artists abused its use, leading Shogun Tsunayoshi Tokugawa to prohibit its use by decree in 1682.
The excellent quality of the decoration, the finely executed details, the depth of the relief, the mark, the perfectly controlled casting of the alloy, and the complete and prestigious imperial symbolism make this an exceptional Japanese mirror. It was not intended for everyday use, as it is far too heavy (700g); it was likely a gift for a celebratory occasion, perhaps a wedding. Japan, early Edo period, 17th century.
Very good condition, with some minor wear. 119 x 18 mm.
An identical piece is housed at the Cleveland Museum of Art.