Below is a snapshot of the Japanese article on sorei (祖霊) (date: 2006 08 11) and my rendering in English.

Sorei (祖霊)

The word ‘sorei’ (祖霊) refers to the spirits of ancestors and is especially used in Shintō (神道) ritual. In the case of sorei it points to the fact that that a lot of time has passed since death, after which the spirit has lost it’s original individuality, and usually points to the collective body of those spirits as well. It is thought that this notion has been around since the Jōmon period while in the period of the myths of the Nihonshoki and the Kojiki the grief of Susanoo about his dear mother as a spirit (sorei) got recorded as well.

According to Yanagita Kunio, in folk belief, one differentiates between spirits called shirei, (死霊), who will be the target of memorial services within a specific number of years after death, and sorei (祖霊). The shirei loose their individualiy with the performance of ‘matsuriage’ (祀り上げ, ‘elevation’) [rituals] at a specific number of years (depending on the region e.g. 50, 33 or 30 years) after death and are made into a part of the sorei after losing their individuality completely. Shintō’s view on life and death holds that people after death will not go to a far away world of the death, as in Buddhism or Christianity, but will remain in close proximity of the world of the living (in places like the mountains or on sea) and will return to their offspring at the occasions of the Bon festival and the Japanese New Year.

Another opinion with regard to sorei is that one helps them to elevate to kami, and that sorei in that capacity become enshrined at village communities or clans as sojin (祖神) or ujigami (氏神).

祖霊(それい)とは、先祖の霊のことで、特に神道の祭祀で用いられる言葉である。「祖霊」 という場合には、死後かなりの時間が立ち、生前の個性を失ったもの、およびその集合体のこと を指すことが多い。この観念は縄文時代から続いてきたと考えられ記紀の神話時代も、祖霊とし ての母を愛しく思うスサノオの嘆きが記されている。

柳田国男によれば、日本の民間信仰では、死んでから一定年数以内の供養の対象となる霊は「死霊」 と呼び、祖霊と区別する。死霊は供養を重ねるごとに個性を失い、死後一定年数(50年、33年、30年な ど地域により異なる)後に行われる「祀り上げ」によって、完全に個性を失って祖霊の一部となるとす る。神道の死生観では、人は死後、仏教やキリスト教のような遠い死者の世界に行くのではなく、生者 の世界のすぐ近く(山中や海上の他界)にいて、盆や正月に子孫の元に帰ってくると考える。

祖霊はさらに神に昇化するとする考え方もあり、そのような祖霊は祖神(そじん)や氏神(うじがみ) として氏族や村落の共同体で祀られることになる。