Shikigesha (式外社) refers to Shinto shrines that were known to have existed in the early 10th century when the Engishiki Jinmyocho was being written, but were not included in it.
Shikigesha, therefore, were considered "off-register" or "unofficial" shrines that were not recognized by the government as official state shrines.
Shikigesha can be further classified into various categories, including shrines outside the control of the imperial court, those with their own power and influence, shrines that integrated Buddhism into their practices, and shrines managed by Buddhist monks. Additionally, some Shikigesha lacked proper formal shrine buildings.
Shikigesha contrast with Shikinaisha which are shrines that were recorded in the Engishiki.
Kokushi genzaisha are a type of Shikigesha which appear in the Rikkokushi.