ellipsis?

[Taka]

The sentence:

Despite a ten-day visit to Japan that I made in spring 1960, Japanese literature did not enter my awareness until high school, and then only in the most tangential way, when we were assigned to compose haiku in my freshman English class.

I take the sentence as ellipsis, and my interpretation is:

Despite a ten-day visit to Japan that I made in spring 1960, Japanese literature did not enter my awareness until high school, and then only in the most tangential way, when we were assigned to compose haiku in my freshman English class, Japanese literature entered my awareness.

Am I right?

[Tdol]

I'm probably being a bit stupid here, but I don't see the ellipsis.

[Taka]

I'm probably being a bit stupid here, but I don't see the ellipsis.

Then, how do you interpret it from grammatical point of view? I mean, in:

then only in the most tangential way, when we were assigned to compose haiku in my freshman English class.

there is no main clause.

[Casiopea]

Despite a ten-day visit to Japan that I made in spring 1960, Japanese literature did not enter my awareness until high school, and then only in the most tangential way, when we were assigned to compose haiku in my freshman English class, did Japanese literature enter into my awareness.

[Taka]

Inversion! That works better. :)