In a poem where the seasonal theme fulfills its true evocative function, there must be a reciprocity between the season, which expands the scope of the haiku and creates the background of associations for the scene, and the specific scene which points out a characteristic yet often forgotten aspect of the season and thus enriches our understanding of it.
Shigehisa Kuriyama, "Haiku," Kodansha Encyclopedia of Japan, p. 82
Like Lee Gurga, I think what makes haiku unique in contemporary Western poetry is its "introduction of a seasonal consciousness into the poem." But, how to understand the concept and practice of kigo ("season words") in the Japanese tradition and integrate seasonal reference/the concept of seasonality into a non-Japanese culture is challenging and rewarding work.
When we look for seasonal reference in English haiku, a non-season-specific nature image, such as “migratory birds” would likely not meet the definition, as we cannot determine a single season for migration, which occurs in both spring and autumn. This fact points to the prevalence of naturalism as an expectation within English-language haiku. Nature in English-haiku literary culture generally accords with naturalist views, else the image will not be given credence, and the poem will thereby suffer. Another way to put this is that in order for the reader to enter the poem, the images presented need to be experienced or intuited as “true” within a prevailing cultural context. In this light, it might come as a surprise to the English-haiku poet that “migratory birds” (wataridori) is an autumn kigo in the Japanese tradition. Birds arrive from Siberia to winter in Japan, departing in the spring; nonetheless, in the culture of kigo, migrating birds migrate only one way, in one season. This fact offers a first clue that seasonal reference in English and kigo as found in Japan do not rest on the same conceptual basis...
For further discussion on kigo and seasonal reference, please read the full text of Richard Gilbert's essay, titled "Kigo and Seasonal Reference: Cross-cultural Issues in Anglo-American Haiku."
between silent moonlit hills
to be named
Blithe Spirit, 13:2, June 2003
the river makes
of the moon
First Mainichi Anthology of Winning Selected Haiku, 1997
after the bombing
ruins of a bridge
linked by the fog
Knots: The Anthology of Southeastern European Haiku Poetry, 1999.
to the spring wind
mother dead, herbal medicine
(In the essay, Richard Gilbert gives his detailed comments on the haiku above from the perspective of seasonality)
Below are two of my award-winning poems, where, I think, "the seasonal theme fulfills its true evocative function:"
harvest moon rising ....
in the migrant's voice
Second Place, 10th Kloštar Ivanić Haiku Contest, 2013
Judge’s Comment: The year wears on, maybe he is a migrant farm worker, far from his home country. He is working late, the harvest moon rises, huge and yellow over the horizon. Filled with nostalgia, he thinks of his homeland, his family, his life there, as he talks to fellow migrants he holds back tears, but his voice wavers)
bits of yesterday
cling to today
Third Place, Inaugural Janice M Bostok International Haiku Award, 2012
Judges’ Comments (by Jim Kacian and Cynthia Rowe):This ties the natural world with the human -- we drag the dream world into the day with us, for a bit, even as our waking obscures that other “real” world we inhabit. At the same time, snow covers what we knew of the outside, but we recognizes it's still there, beneath the covering, evidenced by its shape