Previous answer is
　 Mumei (Rai Kunitoshi)
無銘(来国俊)

Special feature: Rai Kunitoshi, he was said to be Rai Kuniyuki's son.
There are 2 characters Kanji "Kuni Toshi" and 3 characters Kanji "Rai Kuni Toshi". There is also a theory that they were the same person.
Their activity period is for 40 years. According to that,
it is quite possible to make sword alone.
However, there is a sllightly differance between the two.

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Appraisal Quiz #672 (December 25th, 2021)
Who made this sword do you think ?
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Blade length : 76.2 cm or 30 inches.
Sori : 1.0 cm or 0.39 inches.
Mekugi : 2
Width at the hamachi : 3.09 cm or 1.21 inches.
Width at the Kissaki : 2.10 cm or 0.82 inches.
Kasane : 0.71 cm or 0.27 inches.
Shape : The blade is rather wide and thick with small sori.
Jitetsu :Koitame hada well grained with jinie attach
and small chikei work wondeful texture,
Shinogi ji:Koitame hada masanagare.
Hamon : Niedeki deep nioikuchi Gunome midare
with fat soft feeling ashi.
Boshi is round shape and yakkisage style.

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Answer will be posted at next Appraisal Quiz.

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