6 ideas
A saijiki is a reference book that sorts poetic season words into five seasons (spring, summer, autumn, winter, and New Year). Within each season the words are grouped by topical category, such as the season itself, the heavens, the earth, humanity, observances, animals, and plants. Each entry gives the word, notes on its meaning and associations, and example poems, so the almanac works as both dictionary and anthology of shared poetic experience.
A kigo (season word) does more than name a thing. It places the poem at a point in the year and calls up the whole set of feelings and images that earlier poets have attached to that word. The poet can therefore say little and let the reader's shared seasonal knowledge supply the rest.
The book argues that the round of the seasons works as the frame of the haiku. It situates a brief moment inside a larger, recurring order of time and nature. Without that frame the short poem loses much of its context and resonance.
The seasonal system grew out of classical renga, the linked verse composed by groups of poets. There the opening stanza (hokku) had to name the current season to anchor the session in the real moment of composition. Rules for how many verses each season should run made poets codify which words belonged to which season, and those codified lists became the ancestor of the saijiki.
A season word's season follows poetic convention and the old lunar calendar, not a literal thermometer. For example, the 'moon' alone means autumn, and some festivals fall in seasons that seem wrong by the modern calendar. Reading a haiku this way shows the season is a coded literary signal, not only a weather report.
For haiku written outside Japan, the book proposes extending the saijiki approach instead of copying Japanese kigo wholesale. Poets identify their own region's seasonal phenomena, customs, and observances and gather them into local or international almanacs. This keeps the function of the season word, which is shared seasonal reference, while replacing the Japan-specific content.