A classic model among children, the Shuriken (or Ninja Star) is different from most models in that it involves cutting the paper. If you wish to follow the strict rule of not cutting paper, you may substitute the two halves for two squares folded in half.
The paper here is 15cm x 15cm, single-sided origami paper. Any paper cut into the shape of a square should be usable.
Turn the paper over.
Cut the paper into two equal halves. This can be done by folding the paper horizontally then separating the halves by any method.
Take the bottom half and fold its top edge down to the bottom edge. Crease.
Repeat with the top half.
Fold the left edge over to meet the right edge and crease. Do this with both halves.
Unfold. From here, the steps begin to mirror each other. Be careful to not repeat the steps exactly for both halves because they are supposed to be mirror images of each other, not congruent.
Top Half: Fold the top right edge down to meet the vertical center line and crease.
Bottom Half: Fold the bottom right edge up to meet the vertical center line and crease.
Top (Left) Half: Fold the bottom left edge up to meet the vertical center line and crease.
Bottom (Right) Half: Fold the top left edge down to meet the vertical center line and crease.
Flip both of them over. Keep the Left half on the left and the Right half on the right.
Left Half: Fold the top square's top right corner into its bottom left corner. Fold the bottom square's bottom left corner into its top right corner.
Right Half: Fold the top square's top left corner into its bottom right corner. Fold the bottom square's bottom right corner into its top left corner.
Turn the halves to look like this.
Fold the triangles into the center over the smooth side.
The model should look like this.
Open the halves and place one on top of the other. Make sure the smooth (no flaps or open areas) are facing inwards.
Tuck the bottom flap into the open back of the perpendicular half.
Tuck the top flap into the open back of the perpendicular half.
Turn the model over.
Repeat Steps 16 and 17.
You have completed the Shuriken.