Previous answer is
Mumei (attributed to Kawachi Daijo Fujiwara Masahiro)
無銘(河内大掾藤原正広)

Features: This blade has been awarded the NBTHK Tokubetsu Hozon Token certification, a rare distinction even among Shinto and Shinshinto swords.
At the Token Museum, there are only four or five mumei (unsigned) blades that have been designated Tokubetsu Hozon, reflecting the extremely strict standards required for such a classification.
It is believed that this blade was judged to meet those standards due to its exceptional craftsmanship.
Judging from the hamon, this piece has the potential to be classified as a Juyo Token (Important Sword).
At first glance, it appears to be a suriage (shortened) koto blade.
It is likely that this work is a masterpiece by Masahiro, modified to resemble a koto.
However, certain elements such as the boshi’s return (kaeri) differ from typical koto features.
It is regrettable that the blade was shortened; otherwise, it would likely have passed as a Juyo Token without issue.

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Appraisal Quiz #878 (December 27th, 2025)
Who made this sword do you think ?
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Blade Length: 29.9 cm (11.77 in).
Curvature: None.
Mekugi Hole: 4 (3 plugged).
Width at Base (Motohaba): 2.76 cm (1.09 in).
Thickness of rim (Kasane): 0.55 cm (0.22 in).
Shape: A well-balanced piece with standard width and thickness.
Jigane: Ko-itame hada, well-forged, with utsuri appearing.
Hamon: Ko-nie deki, gunome-midare appearing on both sides of the blade, with tobiyaki (flying temper patterns) within.

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Answer will be posted at next Appraisal Quiz.

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