This is a large bifurcated (two points) yanone done in the karimata shape. Although this type of yanone is often referred to as a “Rope Cutter” in actuality, the primary function was as a flesh cutter used in battle and/or for large game animals.
The early karimata are very thin and it’s easy to see how they can cut. The later karimata from the mid to late Edo period, however, tend to be thicker and have ridge lines. Even though they can still cut, they would not be as effective as the older shapes.
This karimata is mumei, thin, very sharp, a polishing window was opened on one face showing a suguha hamon, and the nakago shows good age. This piece most likely dates from early Edo.
The nakago is 9-7/8” (25.1cm) long, the blade is 3-1/4” (8.3cm) long by 2-1/4” (5.7cm) wide. There are no openings and there is a double piercing on the blade.