Registrar WHOIS: refresher needed

[Dave Zan]

Guys, is the registrar required to show complete full WHOIS info, showing who
is the registrant, the contacts, etc.?

I ask this because there's one registrar, yesnic, that's not showing the full
WHOIS info of a domain that's supposedly spamming someone. I'm trying to
help that someone possibly track down the registrant.

The alleged spamming domain, btw, is DOUBTNAHKG.COM.

Thanks!

Never mind, finally found the answers from icann's site. Please disregard.