the real enemy lies elsewhere; there are ulterior motives
Idiomatic expression originating from the historical event 本能寺の変 (Honnō-ji Incident). Used when someone's apparent goal is a diversion and their true objective is hidden. Often employed in strategic or political contexts.
See also: 本能寺の変
His sudden kindness might mean his real objective lies elsewhere.
交渉の場では、敵は本能寺にありと心得よ。
In negotiations, remember that there may be ulterior motives at play.
The historical event (Honnō-ji Incident) from which this expression derives. 敵は本能寺にあり is the idiomatic phrase used metaphorically, while 本能寺の変 refers to the actual 1582 event.
Standard kanji spelling for this idiomatic expression.
Alternate spelling using 在り for あり; less common but attested.
From the historical Honnō-ji Incident (1582), where Akechi Mitsuhide reportedly said '敵は本能寺にあり' (the enemy is at Honnō-ji) to mislead his troops about his true target, Oda Nobunaga. Now used idiomatically to indicate hidden motives.