Dewa では (1)
Double particle (made up of de and wa) meaning :
in, at, as for, judjing from, by
Used in the same manner as de, the addition of wa
serves to stress the preceding word.
1. After noun
東京では物価が高すぎます。
Toukyou dewa bukka ga takasugimasu.
In Tokyo prices are too high.
数学では彼はほかのクラスメートよりも優秀です。
Suugaku dewa kare wa hoka no kurasumeeto yori mo
yuushuu desu.
In mathematics he is superior to all his classmates.
私の意見ではこちらの方がいいと思います。
Watashi no iken dewa kochira no hou ga ii to omoimasu.
In my opinion, I think this is better.
あの様子では彼は来そうもない。
Ano yousu dewa kare wa kisou mo nai.
Judjing from the looks of things, he doesn’t seem
he’ll come.
私の時計では１時１５分です。
Watshi no tokei dewa ichi ji juu go fun desu.
It is one fifteen by my watch.
Japanese for Beginners