plotting to damage an imperial palace or tomb
Archaic legal term from the ritsuryō codes, classified as one of the eight grave offenses (八虐). Refers specifically to conspiracy against imperial structures.
See also: 八虐
謀大逆 was one of the serious crimes under the ritsuryō system, referring to plotting harm against the imperial palace or tombs.
A Sino-Japanese compound formed from 謀 (plot, conspire) and 大逆 (great treason). The exact historical derivation is uncertain; the term appears in classical legal texts.