This is an interesting tantô from the Muromachi era of the sixteenth century. It is signed with the two character signature Masatsugu (正次). There were many smiths who signed using this name from various schools and time periods. This sword has NBTHK papers specifically attributing it to the Muromachi Jidai (Era). When I look at this sword it reminds me of works from the Bingo Mihara school. There was a smith from this school who signed Masatsugu who worked around 1501 so this could be the maker of this blade.
This blade has a nagasa (cutting edge) of 8.7 inches or 22 cm. The width at the moto-haba (base) is 0.85 inches or 2.2 cm and the width at the kissaki (point) is 0.64 inches or 1.6 cm. The blade has a somewhat wide kasane (thickness) of 0.26 inches or 0.7 cm. It could almost be classified as a yoroi doshi (armor piercing tantô). It has a long tang measuring 3.75 inches or 9.5 cm. It has almost no sori (curvature).
The jihada (grain of the metal) is a very fine ko-itame (wood grain) with only a very few slight openings in the laminations as one would expect to find in a blade of this age. The hamon (temper line) is suguha (straight) with a very slightly undulating (notare) here and there.
The blade is in good condition with an old but serviceable polish. There are no flaws and only a few scratches and rubbings here and there. There is no active rust.
This blade comes in a very attractive aikuchi style lacquered wooden koshirae (mounting). It is black with profuse amounts of gold flecks throughout. Also there is a large plum branch with blossoms on one side of the saya with the end of the branch carrying over to the reverse side. This lacquer is in excellent condition with no chips or losses to mar its beauty.
As noted above, the blade has NBTHK Hozon papers (worthy of preservation) that attest to the age attribution and the quality of the sword.