Origami/Techniques/Yoshizawa-Randlett system

Many origami books begin with a description of basic origami techniques which are used to construct the models. The folds are normally described using the Yoshizawa-Randlett diagramming system. There are two main types of origami symbol, lines and arrows.^[1] The arrows show how the paper is bent or moved. Lines show various types of edges:

• A thick line for the edge of the paper
• A dashed line for a valley fold
• A dashed and dotted line for mountain folds (there may be one or two dots per dash depending on the author)
• A thin line for a previous fold
• A dotted line for a previous fold that's hidden, or sometimes a fold that's not yet made.

• 
  Side color
• 
  Crease
• 
  Invisible line

• 
  Valley fold
• 
  Mountain fold
• 
  Fold and unfold valley
• 
  Fold and unfold mountain
• 
  Pleat fold
• 
  Pull
• 
  Inside crimp fold
• 
  Outside crimp fold
• 
  Inside reverse fold
• 
  Outside reverse fold
• 
  Open
• 
  Sink
• 
  Inflate
• 
  Roll
• 
  Cut
• 
  Repeat action

• 
  Rotate
• 
  Turn over
• 
  Zoom in
• 
  Zoom out

There are some symbols that have been used by some authors but are not accepted into the Yoshizawa-Randlett system. Robert Lang has introduced a “view from here” symbol that looks like an eye which has proven to be very useful, especially with his signature three-dimensional models.

• 
  View from here

Several different methods have been introduced to point out to the folder to pay attention to a certain spot; these range from a letter or number to a circle, dot, or other geometric symbol.