“Shirasaya” translates to “white scabbard”. It’s a type of Japanese sword mount made of plain wood which is intended as a storage for the blade. A blade with this type of mounting is never intended to be used for cutting due to the lack of tsuba and wrapping on the tsuka (which provides grip on the handle).
The Shirasaya Katana is a perfect companion of the Shirasaya Wakizashi making them a daisho (paired set).
The video below shows the difference in flexibility between the 1st Generation and 2nd Generation. The 2nd Gen is more flexible like a 1060 blade.
More subtle wire brushed hamon which looks like a real hamon.