その中なか

expression

in it; within that; among them

A demonstrative phrase meaning inside or within something just mentioned. その中に often points to something located inside it; その中で often means within that group, situation, or context, i.e. among them.

• 箱はこを開あけると、その中なかに古ふるい写しゃ真しんが入はいっていた。

  When I opened the box, there were old photos inside it.

• 候こう補ほは五ご人にんいる。その中なかで彼かれが一いち番ばん若わかい。

  There are five candidates; among them, he is the youngest.