One of the simplest folds in origami, involving folding a flap of paper upward and usually toward the folder, forming a valley. In most diagrams showing how to fold an origami model, valley folds are denoted by a simple dashed line. When instructions for how to fold a model simply say "fold," it can be assumed that the required fold is a valley fold.
Step 1: valley fold diagonally both ways.
by Fraze May 15, 2006