Negation is a curious but often overlooked part of translation. Translation does more than carry a text from one language to another. It also pushes aside what does not fit, blocking access to the original so that the new version can stand on its own. This article looks closely at this kind of negation through the idea of “foreclosure,” a concept developed by Jacques Lacan and later used by Gayatri Chakravorty Spivak to describe how certain voices are erased before they are even recognised. By examining Thai versions of two European works with “Oriental” themes — The Mikado and Der Pilger Kamanita — this study shows how translation can completely reject the source text in order to make room for Thai language and culture at a key moment in their development. In these translations, the West is not simply adapted but actively shut out. This move reflects both a deep desire to define Thai cultural identity and an anxiety shaped by long, unequal encounters with Europe. Seen this way, translation becomes a kind of cultural self-defence against Western influence.