origami, one concept per page
Twenty-four lessons on what origami is and where it began, the valley fold and the mountain fold, reading the Yoshizawa-Randlett diagram signs, choosing kami and other papers, cutting a true square and finding the grain, the square base and the waterbomb base, the bird base, the petal fold, the sink fold, inside and outside reverse folds, the squash fold, sharp creases and the bone folder, the paper crane and senbazuru, the flapping bird and action folds, the 1498 paper boat, the fortune teller, the seven fold axioms, Maekawa and Kawasaki flat fold rules, reading crease patterns, Sonobe units that lock, wet folding, troubleshooting torn tips and uneven flaps, a first crane from square to finished model, and teaching a fold to someone else.
One fold, one sign, one honest page. That's a lesson.
origami, one concept per page
Twenty-four lessons on what origami is and where it began, the valley fold and the mountain fold, reading the Yoshizawa-Randlett diagram signs, choosing kami and other papers, cutting a true square and finding the grain, the square base and the waterbomb base, the bird base, the petal fold, the sink fold, inside and outside reverse folds, the squash fold, sharp creases and the bone folder, the paper crane and senbazuru, the flapping bird and action folds, the 1498 paper boat, the fortune teller, the seven fold axioms, Maekawa and Kawasaki flat fold rules, reading crease patterns, Sonobe units that lock, wet folding, troubleshooting torn tips and uneven flaps, a first crane from square to finished model, and teaching a fold to someone else.
Set in Space Grotesk, Inter and JetBrains Mono (SIL Open Font License).
Every fact in this book is as the primary source states it, fetched and read during this build: the Wikipedia articles Origami, History of origami, Origami paper, Orizuru, Mathematics of paper folding, Yoshizawa-Randlett system, Sonobe, Wet-folding, Action origami, Modular origami, Crease pattern, Kawasaki's theorem, Huzita-Hatori axioms, Paper, Paper fortune teller, Thousand origami cranes and Akira Yoshizawa, plus the Peoria Riverfront Museum educator guide Folding Paper: The Infinite Possibilities of Origami and the University of Washington Math Circle paper folding worksheet, all cached at build time and cited in each lesson's source line. General information about how origami works, not advice. An honest no-demo book: no paper was folded and no photograph was staged by this machine; every fold claim is stated as its source states it. Rituals stated as this book's own plan (the lesson order, the practice asks, the first-crane checklist, the troubleshooting pairs) are labeled as this book's plan. No product recommendations. Not affiliated with or endorsed by Wikipedia, the Peoria Riverfront Museum or the University of Washington. No facts from Reddit, forums, vendor blogs or search engines.
Your purchase is for personal use only. You do not have redistribution rights: please do not share, resell, or republish this book or its pages.
© 2026 Steve Hodgkiss. All rights reserved. Personal use only; no redistribution rights.
Edition 1.0 · stevehodgkiss.net
Contents
Per the Wikipedia article Yoshizawa-Randlett system, the two main types of origami symbol are lines and arrows; a dashed line shows a valley fold, where the paper is folded in front of itself; a dashed and dotted line shows a mountain fold, where the paper is folded behind itself, normally done by turning the paper over, folding a valley fold and then turning the paper back over again; a thick line shows the edge of the paper; a thin line shows where a previous fold has creased the paper; a dotted line shows a previous fold hidden behind other paper or a fold not yet made.
Valley and mountain
Every crease is one of two kinds. A dashed line is a valley fold: the paper is folded in front of itself, toward you, like a book page.
A dash and dot line is a mountain fold: the paper is folded behind itself, away from you. The trick the sources give: turn the paper over, fold a valley, turn it back.
Valley and mountain are the same crease seen from opposite faces. Fold one of each into the same square and flip it: each becomes the other.
Fold one valley and one mountain into one square this week; flip it and watch each become the other.
Per the Wikipedia article Yoshizawa-Randlett system, a base is any folded paper that immediately precedes final folding and shaping of the model to be; the kite base is merely two valley folds that bring two adjacent edges of the square together onto the diagonal; the bird base, or crane base, consists of a preliminary fold with both the front and the back sides petal folded upward; the frog base starts from a waterbomb base or preliminary fold with all four flaps squash folded and the corners then petal folded upward.
The bird base
A base is the folded shape immediately before the final folding and shaping. Models are built from it, not from the raw square.
The ladder climbs: the kite base is two valley folds onto the diagonal; the preliminary fold is next; and the bird base is a preliminary fold with the front and the back petal folded upward.
The bird base is also called the crane base: the crane waits inside it. Beyond it, the frog base squash folds all four flaps and petal folds again.
Fold one bird base this week and stop there; hold it and name its four points.
Per the Wikipedia article Yoshizawa-Randlett system, the pleat folds and reverse folds are often done with the two creases at an angle, and reverse folds of a corner are typically used to produce feet or birds heads; the symbol set of the system includes both the inside reverse fold and the outside reverse fold as named operations; and per the Wikipedia article Origami paper, thin paper matters where many folds stack in one small area, as with a bird's legs, feet and beak.
Reverse folds
Reverse folds make the small turns of a model: feet or bird heads typically come from a reversed corner.
The mechanism is the pre-crease: reverse folds are done with the two creases at an angle, both sharpened before anything reverses. Then you choose: inside, the flap slips between the layers; outside, it wraps around them.
These are named operations in the standard symbol set. And they stack paper: a bird's legs, feet and beak fold over the same small area, which is why thin paper wins.
Pre-crease a corner's two angled creases this week before you reverse anything.
Per the Wikipedia article Orizuru, the origami crane is considered the most classic of all Japanese origami; a thousand cranes strung together is called senbazuru, and it is said that someone who folds a thousand cranes is granted one wish; per the Wikipedia article Thousand origami cranes, Sadako Sasaki, two years old when exposed to radiation from the atomic bombing of Hiroshima, developed leukemia; in the book version of her story she folded only 644 cranes before becoming too weak, and died on 25 October 1955, her classmates folding the remaining 356; and per the Wikipedia article Yoshizawa-Randlett system, the crane base is another name for the bird base.
The paper crane
The crane, tsuru, is the most classic of all Japanese origami. Its foundation is the crane base: the bird base, preliminary fold with petal folds front and back.
String a thousand and you have senbazuru: whoever folds a thousand cranes is granted one wish, so it is said.
Sadako Sasaki, two years old at the Hiroshima bombing, folded 644 cranes before she died on 25 October 1955; her classmates folded the remaining 356.
Fold one crane this week from a bird base, any paper, any size; keep the first one.
Per the Wikipedia article Crease pattern, a crease pattern is an origami diagram consisting of all or most of the creases in the final model, rendered into one image, useful for complex models whose steps are too many to draw; their use originated with designers such as Neal Elias to record models, and later Lang, Meguro, Maekawa and Engel designed with them directly; a crease pattern is not fully specified by crease locations alone, because mountain-valley assignment and the stacking order of the folded layers are also required; a pattern is flat-foldable if it can be folded flat without adding new creases; and there is a sequenced crease pattern showing creases up to each fold.
Crease patterns
A crease pattern is all or most of the creases of the finished model in one image: the whole model, no steps.
Designers began using them to record models, Neal Elias among the first; later folders designed straight onto them. Unfold your crane and flatten the sheet: you hold its crease pattern.
Reading one is two decisions the drawing does not make: the mountain valley assignment and the stacking order of the layers; flat-foldable means folding flat without adding new creases.
Unfold your crane fully this week and flatten the sheet: that is its crease pattern.
This book's plan for a first crane end to end, resting on mechanics from the sources: per the Wikipedia article Origami, copy paper of 70 to 90 grams per square meter suits the crane and a flat surface with a bone folder makes sharp creases easy; per the Wikipedia article Yoshizawa-Randlett system, the crane base is the bird base, a preliminary fold with front and back petal folded, each petal lift flattening on pre-creased radial folds, and reverse folds of a corner typically shape feet or birds heads; per the Wikipedia article Orizuru, the crane is the most classic of all Japanese origami; no crane was folded or photographed by this machine, so this order is this book's plan, not a demonstrated run.
Square to crane
The run, this book's plan: cut a true square; pre-crease the four lines and collapse to the square base; petal fold front and back for the bird base, which is the crane base; then the corner reverse folds that typically shape bird heads.
Paper: 70 to 90 grams per square meter copy paper serves. Sharpen every crease on a flat surface.
No crane was folded by this machine; the order rests on the sources. The crane is the most classic of all Japanese origami: worth one honest run.
Fold one crane end to end this week and keep it, creases sharp, first try or fifth.