Substitute signature; a signature carved by someone other than the original smith, often by students or followers.

Substitute signature; a signature carved by someone other than the original smith.

Boat shape; a nakago (tang) shape with a curved profile resembling a boat's hull. Characteristic of Soshu tradition, especially Sadamune.

Swinging-sleeve shape; a nakago (tang) shape with curved, flowing contours resembling a kimono sleeve. Common in Rai school and Soshu tradition works.

Kimono-sleeve shaped tang; a nakago with a distinctive curved profile resembling the flowing sleeve of a furisode kimono, with strong curvature toward the mune. Found on Kamakura tanto.

Two-character signature; a brief inscription consisting of only two kanji characters on the nakago.

Framed signature; the mei portion cut out and inset.

Reverse large diagonal file marks on the tang, opposite to standard direction.

Reverse chisel marks; file marks on the tang running opposite to the normal direction.

Chestnut shape with the edge side higher.

Chestnut-shaped end with the edge side higher; a rounded nakago-jiri variant.

The side of the tang where the edge faces outward.