This is a large, triangular shaped yanone with similar shape open work. The shoulder is a hex shape, and there are some small rust pits and scratches.
The open work on the blade has a beveled edge. Even though this is a larger yanone, it’s not very heavy due to the large cutout.
The nakago is a ¼” (0.64cm) thick at the shoulder and 9-1/2” (24.1cm) long. The blade is 4-1/8” (10.5cm) long by 2-1/2” ( 6.4cm) wide. This yanone dates to the early Edo period.