Sakakuraseki 坂倉関 , Long Wakizashi, KOTO Muromachi period, NBTHK Certificate

This swordsmith had a connection with Muramasa (村正), and according to one theory, he was their apprentice, but this is not certain and further research is anticipated.
The sword follows some of Muramasa's style, such as the fact that the Hamon on the front and back of the blade have the same pattern.
Mino School, late Muromachi period.

Signature : Mumei (Sakakuraseki)
Nagasa : 547mm (21.54 in.) 
Sori : 12mm (0.47 in.) 
Total length : 780mm (30.71 in.) 
Motohaba : 29.3mm (1.15 in.) 
Sakihaba : 17.3mm (0.68 in.) 
Motokasane : 6.7mm (0.26 in.) 
Sakikasane : 3.7mm (0.15 in.) 
Blade Weight : 478g
Total Weight : 740g