Asking for autograph politely


I am a big fan of badminton, especially the Japanese players like Kento
Momota-san, and in a few months they will come to my country, and I would like
to get some of them to sign their autograph in my autograph book. I was
thinking of saying: "サインをください" or "サインをおねがいしますか？", would that be wrong to ask
like that or is there a better polite way of asking?




Taking your suggestions in turn: 「サインをください。」 sounds a bit demanding; it would
be understood, but you can be more polite.

「サインをお願いしますか。」 is not natural, as お願いします is referring to your own wish; the か
at the end rather thus confuses the nature of your wish.

I would probably go with: 「サインをいただけますか。」 -- literally meaning: "Could I
get/receive your autograph?". This is polite, but probably not overly so for
the context you describe.

