expression
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
彼が急に優しくなったのは、敵は本能寺にありかもしれない。
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.
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.