I picked this up mostly as a curiosity and I also like the design. I know it is in rather poor shape. That aside, it is an astounding 8.5 inches (21.59 CM) round. About a half inch thick and is over 7.5 pounds! I believe it is made of iron since it is magnetic and it has an bronze-like (brass) patina? It is signed on both sides Bushu Ju Masanobu.   So many questions : Was this made to sell on the docks for westerners? Was this a presentation tsuba given as a gift to some