expression
now is the critical moment; this is the place
An emphatic phrase used when a decisive moment or important opportunity arrives. Often followed by 〜という時, 〜というところ, 〜とばかり, etc. The literal meaning 'this is the place' can be used in dramatic or figurative contexts.
ここぞという時に力を発揮する。
I show my strength at the critical moment.
ここぞとばかりに攻め込んだ。
They attacked as if this were the decisive moment.