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It might not be an "R". Might be kanji that looks like an "R" :shrug:

edit : Actually on further googling it is 尺 = shaku like the flute Shakuhachi 尺八

Sorry can't make out the 2nd...

To my eyes, the kanji on the box matches that on the blade so I'd say it's a Tosuke.
He did use gold colored fill on the kanji of some razors also.

Can you see a weld line ? If not it could be...