Given the extreme shortness of the poem, the stylistic interest or hitch cannot but consist of the most elementary of rhetorical devices: oxymoron and hyperbole. I use these terms in their widest senses, "oxymoron" covering a whole range of meanings from contradiction to opposition to contrast,...
-- Koji Kawamoto, “The Use and Disuse of Tradition in Basho's Haiku and Imagist Poetry,” Poetics Today, 20:4, Winter, 1999, pp.713, 714.
The rhetorical term oxymoron, made up of two Greek words meaning "sharp" and "dull," is itself oxymoronic: illogical and self-contradictory. Oxymoron is the "show-off" figure of speech mainly used to "shock" the reader into recognizing a reality never noticed before, thus giving voice to life's inherent conflicts and incongruities. Since haiku don't have enough space to deal with the complex narrative logic or explore complicated themes, the use of antithetical phrases and images is one of the most effective ways of instigating the reader's inquiry into and discovery of significance. And evaluated in the context of haiku poetics, "contradiction is an essential element of haikai -- ... the utterly indispensable opposition of ga ("elevated") and zoku ("unrefined") and the logical discrepancies. Basho's disciples and later poets often identified toriawase ("matching of elements") as the fundamental feature of haiku. No doubt the practice of bringing together essentially disparate elements was always at the forefront of their minds" (Koji Kawamoto, The Poetics of Japanese Verse: Imagery, Structure, Meter, p. 108)
Awfully Good Haiku:
snow on snow ...
my shadow and I
Comment: L1 establishes the seasonal and emotional context of the poem while Ls 2&3 convey a strong sense of loneliness and isolation through the rhetorical expression of oxymoron (my shadow and I [i.e. just one person, the speaker] "alone" "together")
At Sumadera Temple --
one hears an unplayed flute
in the dark beneath the summer trees
Comment: On a summer night, standing alone under the dense trees on the Buddhist temple grounds, one can recognize in this oxymoronic announcement ("one hears an unplayed flute") a paradoxical yet transcendent truth: the sound of silence is a purer kind of music than anything that can be played upon an instrument. And armed with the extra-textual knowledge about Taira no Atsumori's beloved flute left to Sumadera Temple after the young warrior's death at the 1184 battle of Ichi-no-tani (Kawamoto, Ibid.), one can see L2 not only as a bold announcement where a paradoxical yet transcendent truth is embedded but also as a heartfelt description of one's mental picture, which adds emotional weight and psychological depth to the poem)
even the crow's caw
full of light
Comment: L1 sets the scene and establishes the seasonal context while the mood and feel of the poem is greatly enhanced through the excellent combined use of oxymoronic hyperbole and synaesthesia in Ls 2&3.
In this haiku, oxymoron is generated not by any particular linguistic structure (such as in the case of Basho's haiku) or form of expression (such as in the case of Chen-ou Liu's snow haiku) but mainly through the meanings and associations of the words themselves by the creation of an opposition or contrast between elevated ("ga," represented by spring skies) and unrefined ("zoku," represented by the crow and its caw) registers (Kawamoto, Ibid., 112).
In order to enhance the mood and feel evoked by the warm and joyful scene, "spring skies," the auditory image, "the crow's caw" (the hoarse raucous sound), is beautified and described with the visual phrase, "full of light" in a hyperbolic manner as indicated by the use of even ("the force of hyperbole is frequently borne by the appearance of the particle "mo" ("even;" for more examples, see Kawamoto, Ibid., pp. 79-82)