British Spiritualism is the closest thing to Shinto in the western world . You could say that spiritualism is the spirit-mythology of the post-industrial western world. Although you could not adopt Shinto practice with cultural observances like those of Japan's you could easily adopt Spiritualism. Spiritualism could be called a sort of British Shamanism. It was propagated in a period of history when British Empire was encountering yoga and asia. I think it originated in France to begin with though (hence, 'seance'). The French colonial powers when they went to Vietnam also influenced their shamanism and developed the quixotic hodge podgeness of Cao Daism of a certainty. Vietnamese are religiously eclectic. The most similar thing to Spiritualism in Asia I think is Vietnam
song,
The Dreams Of Swedenborg by Therion
Spiritualism is indeed more similar to Shinto than Reiki is to Shinto which would come as a surprise to many . Spiritualism like Reiki also has the laying on of hands and it also features transference of profane for sacred energy . However, unlike Reiki which is master to student, Spiritualism can be done independently, alone, like Shinto.
Also see Len Dong (Vietnam) & Cao Daism, and Muism (Korean Shamanism)
books / bibliography,
Occult Japan : Shinto , Shamanism, Or The Way Of The Gods by Percival Lowell
The Essence Of Shinto : Japan's Spiritual Heart by Motohisa Yamakage
Ghosts Of War In Vietnam by Heonik Kwon
Kut : Happiness Through Reciprocity by Hyun-key Kim Hogarth
Shamanism In Korean Christianity by Jang Nam Hyuck
Korean Shamanism -Muism by Dr. Kim Tae-kon & Dr. Chang Soo-kyung
The Darkened Room : Women, Power, And Spiritualism In Late Victorian England by Alex Owen
The History Of Spiritualism by Sir Arthur Conan Doyle