minor festival; off-year festival
A smaller festival held in years when the main festival (本祭り) does not take place, often with reduced scale or events.
See also: 本祭
Since the main festival isn't held this year, a minor festival will take place instead.
陰祭りでは、神輿の数が少なくなることが多い。
During the off-year festival, there are often fewer portable shrines.
Standard spelling.
Abbreviated form; less common but still used.
陰 (kage, 'shadow' or 'hidden') + 祭り (matsuri, 'festival'), referring to a festival held in the 'shadow' of the main one.