How can 関係 be used when there is only one subject?

Question

In my textbook there is a clause that I don't really understand:

なぜ占い好きと関係があるというと、、、

So my understanding takes me this far:

• It's a question asking why 占い好き something
• It's asking why something about relationship(s) - or why relationships to 占い好き exist?

My problem here is: 関係 means relationship right, so I would expect to see at least two things references: ie why is there a relationship between 占い好き AND X? ...but here there is no X. To me the question just seems to be: why　is there a relationship between 占い好き ... huh?

Any comments much appreciated!

Answer 1

I think the sentence is about to explain how "IT" is correlated with 占い好き. And "IT" must be something in the previous sentences or paragraph. It is common to omit pronoun in some cases. The full sentence may be:

なぜこれが占い好きと関係があるというと、、、

Answer 2

You are right. Using two nouns or phrases are expected when you refer to any relationship as follows.

[鶏]{にわとり}と[卵]{たまご}の[関係]{かんけい} The relationship between chicken and egg.

AとBの関係 or AとBは関係がある are broadly used. However, it doesn't necessarily mean you have to always use two nouns as either of them could be omitted or implied.

It is quite common to drop a pronoun or subject in Japanese and without reading further context, it is not possible to know what is referred to in relation to '占い好き'.