Start with a square sheet of paper
Fold the paper in half to make a rectangle
Unfold it
Fold the paper in half the other way
Unfold it
Cut or tear the paper into two equal rectangles if needed
Fold one rectangle corner to corner to make a triangle
Fold the triangle in half again
Unfold and use the crease as a guide
Fold the top and bottom edges toward the center line
Repeat with the second rectangle if making a two-piece shuriken
Fold each piece into a narrow strip with angled ends
Fold one end of each strip into a small triangle
Flip and fold the other end in the opposite direction
Interlock the two folded pieces by sliding the points into each other
Tighten the folds so the shape locks together
Flatten the shuriken evenly
Adjust the points so the shape is balanced