Within my small library of haiku-related material, there are two discussions of Shinto and haiku that I know of: Blyth, in vol. 1 of
Haiku, in Section I, "The Spiritual Origins of Haiku," part 10. Shinto; and Joan Giroux discusses Shinto in a few places in her book,
The Haiku Form.
This is how Blyth starts out his discussion about the relation of Shinto to haiku:
The relation of Shinto to haiku is a vital one, but owing to the obscurity of the nature of Shinto it is difficult to write clearly on the subject. With Shinto and its boring and repulsive mythology, haiku has little to do, directly or indirectly, but primitive, or crude Shinto, which still persists throughout Japan, both expresses the national character and affects it. As far as it concerns haiku, there are two aspects of this Shinto which we must describe, animism and simplicity.
Blyth does not give any examples in this short essay of Shinto-influenced haiku, as he does for example when discussing the influence of Confucianism on haiku.
Joan Giroux, after a very brief introduction to Shinto beliefs and practices, points out that:
The communal aspects of Shinto did dovetail nicely with the utopian theories of Confucianism. But the Shinto word 'kami' (translated into English by 'gods') really indicates the animism which is the essence of Shinto. Animism is a primitive belief which endows even inanimate things with both life and spirit to explain two phenomena: first, the difference between a living man and a corpse (described as caused by the disappearance of life from the body), and secondly, the existence of dreams (explained as the ability of the spirit to move about.) Shinto, with its belief in the many 'kami' or minor deities of mountains, streams and trees, is a religion of nature worship. This fact is reflected in the large part played by nature in Japanese haiku.
Giroux's remark about dreams makes me think about Basho's death-verse in a new light:
tabi ni yande yume wa kareno o kakemeguru
ill on a journey:
my dreams roam round
over withered fields
--Basho, Tr. Barnhill
Although there is clearly a Buddhist element here, is there also a Shinto element as well?
As others have pointed out, there are haiku about various Shinto places, practices, and festivals. Basho wrote haiku about visiting sacred mountains. He wrote a haibun, Visiting the Ise Shrine," which contains the haiku (also in "Knapsack Notebook"):
nami no ki no hana to wa shirazu nioi kana
from what tree's
blossoms I know not:
such fragrance
--Basho, Tr. Barnhill
Barnhill points out that this haiku is a 'take-off' from a waka by Saigyo, which includes these lines translated by Barnhill: "What divine being / graces this place / I know not...."
On another visit to a shrine, Basho wrote (in "Journal of Bleached Bones in a Field"):
misoka tsuki nashi chitose no sugi o daku arashi
month's end, no moon:
a thousand year cedar
embraced by a windstorm
--Basho, Tr. Barnhill
Ueda notes that Basho wrote this "when he visited one of the Grand Shinto Shrines in Yamada..." The commentator Tosai points out that "...the Outer Shrine [is worshipped] as a moon deity. With no moon, the invisible deity seemed even more august, and the poet looked up to the cedar tree as her holy manifestation."
Blyth has two kigo/topics related to Shinto in his 4 volume "Haiku": in Spring, under "Gods and Buddhas," there is "The Shrine of Ise," and in Autumn, under "Gods and Buddhas," there is "The Gods' Absence." Perhaps "The Feast of All Souls" in Autumn is also related to Shinto?
I will close with a haiku by Issa which seems to me to reveal how pervasive Shinto is in Japanese people. Issa was a Pure Land Buddhist (if I'm remembering correctly) and yet, when he visited the Inner Precincts of Ise Shrine, he wrote:
onozukara koube ga sagaru nari kamiji yama
Kamiji Yama;
My head bent
Of itself.
--Issa, Tr. Blyth
Larry