ましては

ましては
conjunction
let alone; much less; even more so
1. let alone; much less; (and) even more so
Literary conjunction used after a milder case to introduce a stronger one. 'If even X is the case, then certainly Y too' — typically marking the second item as a more extreme example of the same point.
大人(おとな)でも(むずか)しい。ましては子供(こども)には無理(むり)だ。
It's hard even for adults — much less for children.
(ある)くのもつらいのに、ましては(はし)るなんてとても無理(むり)だ。
Even walking is hard, let alone running.
専門家(せんもんか)でも判断(はんだん)(まよ)問題(もんだい)だ。ましては素人(しろうと)即答(そくとう)できるはずがない。
It's a question even experts find hard to judge — there's no way amateurs could answer it on the spot.

Formal conjunction at the start of a sentence. The structure compares two cases: the first is conceded to be already extreme, and the second is presented as obviously more so. Often pairs with なんて, でも, or はずがない at the end.

REGISTER:

  • Written and formal speech. In casual conversation, まして or {まして}や は more common.
  • The full ましてや is interchangeable and slightly more emphatic.

SIMILAR EXPRESSIONS:

  • まして: shorter form, same meaning — more conversational
  • ましてや: emphatic version — adds rhetorical weight
  • なおさら: all the more — similar logic but with positive cases ('all the more reason')
  • どころか: far from being — contrastive, focuses on contradiction rather than escalation