This is a rare signed presentation yanone, signed Masayoshi on the nakago. Presentation yanone are very difficult to find and rarely come up for sale, this piece was in a collection for over 40 years, the theme is butterflies. The blade has a new shirasaya.
The two images of the mei were made in different light to show the kanji easier. To judge the quality of the open work on this type of yanone, spin the yanone on the tip and see if the open work jumps back and forth. If it jumps the shape is not symmetrical. This yanone does not have that problem, it is a good one.
The nakago is 6-7/8 inches (17.5cm), the blade is 5 inches (12.7cm) long by 4-1/8 inches (10.5cm) wide. The Yanone comes in a new shirasaya.