noun
memorial service for the war dead
A ceremony to honor and comfort the spirits of the deceased, especially soldiers killed in war. Often associated with Shinto or state-sponsored observances.
毎年、靖国神社で招魂祭が行われる。
A memorial service for the war dead is held every year at Yasukuni Shrine.
慰霊祭 is a more general memorial service for the dead, not limited to war dead, and is used in both religious and secular contexts.
Compound of 招魂 (shōkon, 'inviting the spirits') + 祭 (sai, 'festival' or 'ceremony'). The term is historically associated with Shinto rites for the war dead.