Previous answer is
Mumei (attributed to Den Ichimonji)
無銘（伝　一文字）

Features:　This sword was appraised as "den Ichimonji" by the NBTHK (The Japanese Sword Museum).
Dr. Tanobe also identified it as Ichimonji. Ichimonji school is divided into Fukuoka, Yoshioka, Katayama, Ko-Ichimonji, etc.
From the quality of this piece, it is believed to be a Fukuoka Ichimonji work rather than a general Ichimonji attribution.

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Appraisal Quiz #849 (May 31st, 2025)
Who made this sword do you think ?
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Blade Length: 72.9 cm (28.70 in)
Curvature: 1.67 cm (0.66 in)
Mekugi Hole: 2
Width at Base (Motohaba): 3.22 cm (1.27 in)
Width at Tip (Sakihaba): 2.39 cm (0.94 in)
Thickness of rim (Kasane): 0.76 cm (0.30 in)
Sword Weight: 840 g
Shape: Wide mihaba, carved with bohi on both sides, deep curvature, and an extended boshi.
A magnificent and robust blade.
Jigane: Fine ko-itame hada, densely forged and of excellent quality, with utsuri appearing clearly.
Hamon: Near the hamachi, a deep nioiguchi chōji-midare with active ashi.
Boshi shows midare-komi and turns back in a small circle.

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Answer will be posted at next Appraisal Quiz.

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