The accordion structure comprises a large group of books and variations, including orihon, sempuyo, nobiru gajo and nori-ire gajo, each of which is of such importance and versatility that it will be treated separately.

The scroll might be compared to a modern cassette tape – to find some particular passage the scroll must be spooled through until the required passage has been located, in much the same way that a cassette must be wound back and forth until the right track has been found. The development of the book, with its discrete pages, represents as much of an advance on the scroll as the Compact Disc on the cassette – one can immediately jump to whatever page one wants.

Orihon
The orihon structure was developed during the Heian period (794–1185), and was traditionally used for Buddhist sutras. It is thought that if an orihon book inscribed with Buddhist sutras is 'cascaded' from hand-to-hand, the draught created by the falling pages has healing properties if directed to the affected part of the sufferer's body. In Japanese Buddhist monasteries it is still sometimes possible to receive this treatment.

The orihon structure developed out of the scroll simply by folding the scroll into an accordion-fold and pasting it between covers. In this form it was both easier to access and to store and, although not yet truly a 'book-shaped' book this was the vital step in its development. Structure The basic orihon book consists simply of an accordion-folded sheet of paper bound within soft or hard covers. The paper can be a single long strip, or several smaller strips pasted together. Traditionally, smaller sheets would be pasted into a long strip with little regard paid to where the joins fell; as the style developed, however, the joins were usually planned to fall at the page folds.

If the flaps all fall at the same (usually fore-) edge, the book will have greater thickness one side than the other; for this reason if there are to be a great number of joins they are sometimes placed at the back- and fore-edges alternately, even though the back-edge joins are more visible than the fore-edge joins. If an even number of pages is used, the book will have a definite 'front' and 'back'; if an odd number of pages is used, the concepts of 'frontness' and 'backness' may be more equivocal – either doubling the capacity of the book, or enabling a double book not dissimilar to the Western dos-à-dos structure.

Alternative orihon page construction methods

There may be no endpapers; the main pages may be attached to the covers by means of a narrow tab which is overlaid with a single sheet of decorative paper; or an extra page-pair of a decorative paper may be used.

Most of the illustrations in this section are temporary; they will be replaced with the final pictures shortly.

Three Envelope Books
a set of nori-ire gajo books made from old envelopes; by the author

Applications
A common use in the West is in children's books; room friezes are often packaged orihon-fashion, and some board books are constructed in orihon form, occasionally with integral covers (see Children's Board Book, right). The form is also frequently used in advertising leaflets which, although consisting of no more than a single sheet of folded paper, might properly be considered orihon books (seeAdvertising Leaflet, right).

The book artist may find the orihon indispensable for two or three of its characteristics:
• while it is possible to read each page or pair of pages individually, it is also possible to view all the pages at once, or in non-contiguous groups.

Non-contiguous arrangement of pages of an
orihon alphabet book

This is a very useful attribute in the case of panoramic pictures, time-line diagrams, and some records of performance and conceptual art, for example, Horizon to Horizon and Alps Horizon by Hamish Fulton; the all-at-one-view property is exploited in various books by Sarah Jackson. In England orihon-form maps, showing the route between only two towns – stylised but showing landmarks and road junctions – were known as 'stagecoach maps'. (See The Northern Line, flat, right,for a modern equivalent of the stagecoach map by the author.)
• because of their compound action, orihon books can be very useful as scrapbooks. Guarding of the pages is unnecessary – however thick the scraps in the book, so long as they are not too close to the folds, the book will simply expand uniformly (see Scrapbook, right).
• Sometimes the orihon is used for no apparent reason other than that it is attractive and unusual. Perhaps it is for no deeper reason than this that it is used for such books as Tony Hayward's Indian Sandwich series, 1994, right.
• When opened, the orihon book can assume a very sculptural form (see The Northern Line, fanned, right).

Album books
Nori-ire gajo
An alternative construction is to paste the separate pieces of paper together at the fore-edges, album-style (nori-ire gajo). This results in no increase in thickness even though all the joins are at the fore edge, and also means that the fore edge can be guillotined for a uniform finish; however, it is not possible for the book to be opened flat to show more than a two-page spread.

Although similar in appearance to the orihon, album-style bindings are a separate development in that the pages are of individual pieces of paper assembled into a book rather than formed by folding a scroll.

Nori-ire gajo construction
Since each two-page spread is composed of a separate piece of paper, if desired each could be of a completely different paper, or a series of pages not originally intended for binding, eg small posters. This useful property is shared with many Japanese book structures, eg nobiru gajo, detchoso, sempuyo.

Nori-ire gajo construction

Nobiru gajo
The orihon book with double-leaved album pages (nobiru gajo). is similar in appearance to the nori-ire gajo but the separate pieces of paper, each twice the page width, are folded in half, text-side inward, and tipped together at both the fore and back edges.

Nobiru gajo construction
This results in a much stiffer page than the basic orihon, which may be useful if the book is to stand open self-supported for display. Moreover, since each page is now double, both sides of the page can be written on even with a fluid ink which would bleed through a single page.

Applications
In general, the applications for both nobiru gajo and nori-ire gajo are the same as for orihon books, except that since the book is constructed of two-page spreads joined together, the problems of imposition (the conflict of 'readers' spreads' and 'printers' spreads') will not apply, making this a very convenient vehicle for home computer publishing. This is a major convenience, and one which applies to many Japanese bookforms. For a fuller discussion of this topic, see Appendix II: Imposition.

Moreover, each spread (pair of facing pages) could if required be of a completely different paper. Keith A Smith has described contertina books as offering, 'easily the most potential for variation of any bindings' (Non-adhesive bindings, Keith A Smith, 1992).

Sempuyo
The sempuyo binding was developed during the Heian period, and was more popular in China than in Japan, where few examples are to be found.

Construction
Sempuyo binding consists of an orihon book constrained at the back by a wrapper passing round the back edge, pasted to the fore edges and usually also the back edges of the endpapers. The joining of the fore edges may be by means of flaps, orihon-style or, more neatly, nori-ire gajo style which allows guillotining of the fore edge.

Structure of the sempuyo book

Application of the sempuyo wrapper
The 'wrapping' around the back of the book can be achieved in many creative ways in addition to the traditional sheet of paper. The covers are then attached to this wrapper instead of directly to the endpapers. This construction gives the orihon book a more familiar feel, as it opens and handles more-or-less like a normal Western book. The sempuyo is also known as the 'flutter book' because, although the pages are constrained at the back they are not attached, and if the book is read outdoors all the pages may flutter out of the covers in the breeze, causing some embarrassment to the reader and amusement to onlookers!

Application of the sempuyo wrapper

Orihon-construction children's board book with integral cover

Orihon-construction advertising leaflet

The Northern Line flat

Scrapbook

Indian Sandwich
one of a set of three books by Tony Hayward, 1994

The Northern Line fanned

Applications
This is an extremely useful bookform for the self-publisher and book artist: as well as being elegant and versatile, its pages do not need to be imposed (see Appendix II: Imposition) and if required each pair of pages could be of a different colour or type of paper, or indeed a completely different material altogether (see Makereadies and Flyers, right).

The sempuyo feels very comfortable when held open in the hand, but when opened and placed flat on a table some of the pages will tend to stick up in the air (see Flyers, right). This is because the two halves of the text block (the 'read'part and the 'unread' part) are held apart by the part of the wrapper which encloses the spine. This might be thought of as a disadvantage, but it has been cleverly exploited by the designer of a Compact Disc storage system – as one 'page' is pushed down, the next springs up, presenting one with another CD (see CD Storage System, right).

Makereadies
This book was constructed from scraps of printers' 'makeready' sheets. By the author

Flyers
this book was constructed from found A5 flyers.

CD storage system
based on the detchoso book structure