A Japanese period drama, generally set during the Heian (794–1185 CE), Sengoku (1467–1615 CE), Edo (1603–1868 CE), or Early Meiji eras of Japanese history.
Generally features samurai (or ronin) as main characters, with feudal lords, shoguns, ninjas, peasants, craftsmen and merchants also playing important parts. Often focuses on intense sword-fights between samurai and other sword-wielding characters.
Characters will usually dress in the period-appropriate attire in such works. Some characters (often the more 'regal' or 'authoritative' ones) will speak in a faux "antiquated stage Japanese", analogous to using "thees and thous" and other 'Shakespearisms' in an English work.
Drawn works set in a jidaigeki setting will often feature a sumi-e "ink wash" aesthetic or other elements of traditional Japanese art.
For tagging purposes, any post that depicts a visibly "Medieval Japanese" setting generally counts. Consider this the Japanese culture equivalent of the Medieval tag. Avoid tagging Touhou works with this tag, or other mixed fantastical/sci-fi settings, unless they have the distinct "jidaigeki" feel.
(This may be hard to quantify, but generally, if it feels like a "samurai period piece film", then it counts, even if it's a mixed setting.)
Tag usage notes
Tag jidaigeki for posts that feature a visibly Japanese 'Medieval' theme.
Especially if it focuses on samurai and feudal lords/shoguns, analogous to knights and lords for Western Medieval works.
Avoid tagging jidaigeki for mixed settings unless one is sure that it qualifies.
Avoid tagging jidaigeki for settings that have a central focus on fantastical or 'magical' elements, even if set in the appropriate era.
Generally these will focus on gods, magic, youkai and the like.
e.g. Ōkami (it is also set in prehistoric Japan instead of 'medieval' Japan.)
The analogy is like medieval vs. fantasy. There is some overlap, and some posts may qualify for both. Likewise, some overtly fantastical or 'magical' settings may also feel jidaigeki if there is significant focus on samurai characters (or feudal lords, or "the common people").
Ninjas by themselves generally do not count for jidaigeki.
