I claim the ornamental design for a katana, as shown and described.
FIG. 1 is a bottom plan view of a katana showing my new design;
FIG. 2 is a top plan view thereof;
FIG. 3 is a right-side elevation view thereof;
FIG. 4 is a left-side elevation view thereof;
FIG. 5 is a front elevation view thereof;
FIG. 6 is a back elevation thereof;
FIG. 7 is a bottom perspective view thereof; and,
FIG. 8 is a top perspective view thereof, showing the katana.
The broken-away symbols in the drawings indicate the appearance of any portion of the article between the break lines forms no part of the claimed design. The broken lines depicting a handle are for the purpose of illustrating the unclaimed portions of the article and form no part of the claimed design.