Yoshizawa–Randlett system

The origami crane diagram, using the Yoshizawa–Randlett system

The Yoshizawa–Randlett system is a diagramming system used to describe the folds of origami models. Many origami books begin with a description of basic origami techniques which are used to construct the models. There are also a number of standard bases which are commonly used as a first step in construction. Models are typically classified as requiring low, intermediate or high skill depending on the complexity of the techniques involved in the construction.

History

The concept of diagramming originated in the 1797 book “Senbazuru Orikata”, the first origami book ever published. The diagrams in this book were very unclear, and often only showed the end result of the folding process, leaving the folder unsure how the model was created.

Later books began to devise a system of showing precisely how a model was folded. These ranged from an unwieldy set of symbols to a photograph or sketch of each step attempting to show the motion of a fold. None of these systems were sufficient to diagram all models, and so none were widely adopted.

In the 1950s and '60s, Akira Yoshizawa proposed a system of diagramming. He introduced its diagramming notation in his first published monograph, Atarashi Origami Geijutsu (New Origami Art) in 1954. He employed dotted and dashed lines to represent mountain and valley folds, and a few other symbols such as the “inflate” and “round” symbols. This system caught the attention of Samuel Randlett and Robert Harbin, who added a few symbols such as “rotate” and “zoom in”, and then adopted it as the standard. The Yoshizawa–Randlett system was first described in Samuel Randlett's Art of Origami in 1961.[1] It was then accepted as the default throughout the international origami community, and is still in general use today.

Origami symbols

Basic folds

There are two main types of origami symbol, lines and arrows.[2] The arrows show how the paper is bent or moved. Lines show various types of edges:

Symbols for basic folds
Dashed line shows fold line. Curved arrow with solid arrowhead shows direction of fold. Example shows upper left corner of square paper raised and then brought down on middle of square to form a 45 degree valley fold across upper left corner of paper
Valley fold 
Dash-dot line along fold. Curved arrow with open arrowhead for direction of fold. Example shows lower right corner of square paper swung underneath and past upper left corner to form a 45 degree mountain fold across upper left corner.
Mountain fold. 
Dashed line shows fold line. Curved arrow with a solid arrowhead and a body with an acute angle so the arrow appears bent in the middle. Alternate arrow has a single curved line with a solid arrowhead on one end and an open arrowhead at the other end replaces the acute angle and returning half of the arrow. Example showing a paper with the right edge lifted, brought to touch the left edge, creased in the middle, and then unfolded.
Fold and unfold valley. 
Turn over and invisible line. 

Common operations

The operations shown here are all fairly common. The pleat folds and reverse folds are often done with the two creases at an angle. Reverse folds of a corner are typically used to produce feet or birds heads.

The sink fold is considered an intermediary to high skill. The version shown here is called an open sink and there is another version called a closed sink which generates a triangular pocket with no flaps showing. In simple cases the model can be partly unfolded and then folded with the sink in place.

Origami symbols
Rotate. 
Put the points together 
Open. 
Pull. 
Repeat action. 
Pleat fold, also called an accordion fold. 
Inside crimp fold. 
Outside crimp fold. 
Inside reverse fold. 
Outside reverse fold. 
Inflate the model. 
Sink a corner. 

Compound folds

Origami bases

In origami, there is a series of several bases that many models are created with. In general, "base" refers to any folded paper that immediately precedes final folding and shaping of the model-to-be. The ones listed below are generally accepted as the traditional origami bases.

More advanced skills

References

  1. Nick Robinson (2004). The Origami Bible. Chrysalis Books. p. 18. ISBN 1-84340-105-3.
  2. Peter Engel (1989). Origami from Anglefish to Zen. Dover. p. 8. ISBN 978-0486-28138-4.

Further reading

Almost every origami book has basic instructions and a set of folding symbols. The following are books that happen to have detailed explanations of these techniques, and how the techniques are related to each other:

External links

Wikimedia Commons has media related to Origami.


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