Previous answer is
Mumei (attributed to Ko-Naminohira)
無銘(古波平)

Features:　Ko-Naminohira swords were highly favored by naval officers because the name "Naminohira" (literally "flat waves") symbolized calm seas. These swords originated in Naminohira, Taniyama-go, Taniyama District, Satsuma Province — present-day Kamihabamoto, Kagoshima City, Kagoshima Prefecture.
During the Battle of Ichinotani, a warrior named Ibo Noritsuna, known for his unmatched strength, used a blade crafted by Naminohira of Satsuma Province to take the head of Etchu-no-kami Moritoshi. The nearby coastline of Naminohira was known to be rich in iron sand, making it an ideal place for swordsmithing.
Among existing works, the swordsmith Yukiyasu is considered the founder of this lineage. The Naminohira school is generally categorized into different periods: Kotō (Old Sword period), Ko-Naminohira (Old Naminohira), Chu-Naminohira (Middle Naminohira), and Sue-Naminohira (Late Naminohira). The earliest Naminohira smiths are believed to have been active during the Heian period, including Yukiyasu, Yukihito, Yasunori, Yukimasa, and Yasumitsu.

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Appraisal Quiz #873 (November 22nd, 2025)
Who made this sword do you think ?
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Blade Length: 2 shaku 2 sun 1 bu – 66.9 cm (26.34 in)
Curvature: 5 bu – 1.5 cm (0.59 in)
Mekugi Hole: 1
Width at Base (Motohaba): 3.09 cm (1.22 in)
Width at Tip (Sakihaba): 2.48 cm (0.98 in)
Thickness of rim (Kasane): 0.59 cm (0.23 in)
Sword Weight: 675 g
Shape: The blade has a slightly wide body, thick kasane, deep curvature, and an extended kissaki, showing excellent form.
Jigane: Ko-itame hada, very well-forged with refined steel.
Hamon: Saka-choji midare continues from the hamachi to the boshi.

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Answer will be posted at next Appraisal Quiz.

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