As a genre, Japanese linked verse is referred to as renga. Renku is the name generally reserved for linked verse composed in accordance with the principles advanced by the great master Basho. 
Renku sequences are normally written by two or more persons at a single sitting, poets taking turns to compose individual verses , an arrangement referred to as hizaokori. Occasionally verses are selected by degachi - competitive submission, whereby all participating poets compose a stanza, but only one is chosen for inclusion. Sequences are identified by length:
· - junicho and shisan both containing 12 stanzas;
· - jusanbutsu 13;
· - shishi 16 stanzas;
· - hankasen - half-kasen 18;
·-  nijuin 20 stanzas;
· - kasen 36 stanzas; and
· - hyakuin 100.

An Illustration of Structure - the Kasen 

A renku sequence is not simply a succession or assemblage of verses. There are underlying structures designed to "orchestrate" the piece. In the kasen, as written by Basho, renku reached heights that have remained unsurpassed. A kasen renku is a thirty-six stanza sequence comprising two eighteen stanza folios. Each folio is itself divided into two sections, the "front" and the "back". The first folio front, sho-ori no omote, contains six stanzas, and the first folio back, sho-ori no ura, twelve stanzas. These proportions are mirrored in the second folio. Thus the second folio front, nagori no omote, contains twelve stanzas, and the second folio back, nagori no ura, six stanzas. 
The overall dynamic structure of the kasen renku is described by the expression, jo-ha-kyØ, where
· jo may be understood as "prologue",
· ha as "development" and
· kyu: "conclusion". 
The phases of this dynamic structure are coterminous with the folio divisions . Therefore, the prologue, jo, comprises the six stanzas of sho-ori no omote: the first folio front. The development phase, ha, constitutes the body of the poem and comprises both the twelve stanzas of the first folio back: sho-ori no ura; and the twelve stanzas of the second folio front: nagori no omote. The six stanzas of the second folio back, nagori no ura, form kyu: the poem s conclusion. 
In musical terms, the dynamics of the kasen might be described as:
· larghetto, for the prologue - jo
· con brio for the development - ha
· and in rapid diminuendo for the closure - kyu.

Link and Shift
 
The basic compositional relationship between successive verses in the kasen, as in all renku, is governed by two key principles: "link" - tsukeai, and "shift" - tenji. 
· t sukeai - link: describes the degree and nature of the connection between any given stanza and that which immediately precedes it.
· tenji - shift: is perhaps less immediately intuitive, requiring that a verse bear no resemblance whatsoever to the last stanza but one. 
The renku poet must therefore consider not just the current stanza (the tsukeku) upon which he or she is engaged, with its thematic connection to the preceding stanza (the maeku), but also ensure that there is a comprehensive move away from the thematic content of the stanza before that (the uchikoshi or "leap-over" verse). To paraphrase George Orwell, the concept might be given thus: Maeku...good. Uchikosh ...bad. Appropriately enough, inadvertent repetition of a theme, which has already appeared, is called "regression". 
....... tsukeku ( tsukeai >) maeku ..... current links to preceding 
..........t tsukeku (tenji <) uchikoshi .....but shifts from last-but-one

Tsukeai - Link

Basho identified three broad categories of linkage between adjacent stanzas: by word - kotoba-zuke; by content - kokoro-zuke; and by scent - nioi-zuke. 
· k otoba-zuke - "linkage by word": draws together all the various ways in which a link might be word-driven, or based on verbal reasoning: reference, allusion, association, punning, etc. Basho considered this technique to be typical of classical antiquity
· kokoro-zuke - "linkage by content": describes any direct relationship in the physical universe: material, spatial, or temporal. Direct, narrative, or logical progressions would also be included in this category.
· nioi-zuke - "linkage by scent": was Basho's profound contribution to the theory and practice of tsukeai. It introduced a hither to fore unrealised degree of subtlety. Earlier poets had proposed that the association between stanzas might be based on emotion, but this had amounted to little more than narrative progression. Basho vastly extended this notion to include all states of mind and being. Further, he proposed that a stanza might be regarded as an entelechy, a complete world, into which reader or renkujin might enter, and so find linkage purely through empathy. 
Subsequent poets and scholars have sought to refine the definition of Basho s abstract style of linkage. Four terms describe what is in effect a sliding scale of coincidence: 
· scent nioi: in this specialised sense the most tenuous and indirect of feelings.
· echo hibiki: some part of an object or event finds expression in another.
· reflection utsuri: the general quality of an object or event is reflected in another.
· run-on hashiri: the quality of an object or event is transferred directly to another. 
Three others are also commonly identified: 
· rank kurai: considerations of caste or class constitute the link.
· nostalgia omokage: a relationship based on general cultural iconography, but not direct literary of historical allusion.
· setting keiki: an action set in the ambit of the preceding stanza, or an environment realised from an action expressed in the preceding stanza.

Tenji Shift

Though any verse links to the one that immediately precedes it, it marks a wholesale shift from the verse before that. At its simplest the principle of "shift" ensures that a renku sequence is non-linear, adopts a broad canvas, and cannot be used for the purposes of narrative or polemics. At it s most complex, metaphysical arguments may be advanced which consider the poem to generate a synthetic universe, a mandala of existential symbolism, or some sort of cosmic exegesis akin to divination. Certainly it is significant that the poem is a collective, rather than individual, manifestation. 
In order to ensure the maximum diversity of subject, and minimise the risk of regression, it is common for the sabiki - the "conductor" of a renku session - to refer to a pre-existing schema or list of topics to be treated. No particular order is imposed, but once a topic is "ticked off", it will not be referred to again. Though the schema varies from school-to-school and style-to-style, the practice is of great antiquity, drawing on the earliest traditions of classical linked verse and, ultimately, on its Chinese counterparts. 
The concept of shift does not, however, imply "diversity at any cost". The renku sequence is a single poem, not a collection of random thoughts. So whilst a succession of anodyne sentiments is clearly to be avoided, brutalism or sheer cacophony are also undesirable.

A Questionable Practice

When typesetting a poem, in order to emphasise "link and shift", the stanzas of a sequence are sometimes reproduced twice: AB BC CD WX XY YZ. Whilst this approach might be superficially attractive it should be noted that it does not accord with the Japanese tradition. More seriously it risks introducing the expectation that there should be a high degree of direct run-on between stanzas. Most damagingly it seriously distorts and interrupts the overall "musical" movement of a piece.

The Narrative Perspective

Some core observations on the nature of shift, and the avoidance of regression, were made by the poet Hokushi, one of Basho's disciples. Hokushi divided the narrative perspective of renku into two broad categories: "place" (or "non-person"), - ba; and "person" (or "emotion") ninjo: 
· ba - place: describes any stanza in which people do not figure directly, and which is constructed in an impersonal voice.
· ninjo - person: is itself broken down in to three categories.
· ji - self: employs a first person perspective.
· ta - other: introduces the third person narrative voice.
· ji-ta-han - mixed company (literally self-and-others): is a verse which switches from one to the other. 
It was Hokushi s contention that, as well as considerations of content, no verse in any given trio, current/preceding/last-but-one, should employ the same narrative perspective.
Hokushi's proposal in relation to 'person' verses might be most simply conveyed in English as the declension of the verb (stated or implied): 
ji - self: first person singular or plural, I - we 
ta - other: third person singular or plural, he - she - they 
ji-ta-han - self-and-others: second person singular or plural, you. Or, and more commonly, a rhetorical construction implying direct authorial statement: 'how sad to see the beggar sing'

Prohibitions and Rules

In Basho s day the variety of content and execution was ensured by a set of strictures and injunctions inherited from the wider corpus of traditional linked verse. 
· sashiai - prohibitions: were often phonetic, designed to prevent gross repetitions, mimicry, and other forms of compositional inelegance.
· shikimoku - rules: governed the position of key topics, both their order (and dedicated number of verses) kukazu, and the intervals between their first appearance and re-emergence - sarikirai. 
A simplified example may be drawn from the traditional kasen: Three topics, "moon", "blossom" and "love" are considered absolutely essential. Moon would be expected to feature in the fifth stanza. Two, or perhaps three, stanzas dedicated to love would appear in the ninth, tenth and eleventh positions. Moon would re-emerge in the thirteenth or fourteenth stanza. Verse seventeen would be expected to feature blossom, ideally cherry blossom. Love would again seek to be requited in stanzas twenty-one, two and three. Moon might be expected to take her bow in stanza twenty-nine. And blossom, unfaded, grace the penultimate stanza: thirty-five.

An Honour

· The generic name for a verse in renku is a hiraku
· Contemporary renkujin call the long verse (in Japanese 575) choku . 
. 
· Contemporary renkujin call the long verse (in Japanese 575) chouku.
· The short verse (in Japanese 77) is a tanku. 
However, a consequence of "link and shift" is that certain verses have unique dynamic properties. The first verse, the hokku, is of necessity entirely original. It was from this verse that the haiku originated. The second verse, wakiku, links naturally to its preceding verse, the hokku, but has no last-but-one verse to shift from. The third verse, daisan, is the first of the sequence which can, and must, exhibit both link and shift. Conversely the last verse, ageku, must draw the sequence to a close without generating any "loose ends" or leaving the poem in suspense. These special requirements meant that the honour of completing these verses would be reserved for the highest ranking persons present. Ideally those persons would also be the most skilled poets.

The Beautiful Silence
 
Clearly the intricacies of this poetic form reward study. But the true genius of the successful renkujin lies not in the ability to abide by the rules of composition, nor yet in the skill with which individual stanzas are crafted, but rather in the creation of "that deep silence charged with life" which must be felt between the verses. Renku is a collaborative art-form, yet, as ever, the greatest power of suggestion lies in that which is left unsaid.

© John E. Carley
The Pennines, UK