It is not a trademark as I see it... as it is a real word and could be used for anything (community type site within China being the most obvious).
So you could sell to him it to him I guess - why should they get for free really (if he was your competitor you wouldn't give it to him!

)
Also pretty sure he would not just give it to you, if was the other way around... perhaps is time for us all to teach some of these guys, that they should have secured the IDN version, before pushing off to build a brand!
Also remember that pinyin / his ascii domain is not exact, and that even though domain registration goes back to 2006... it seems he only added the Chinese to clarify the pinyin this September... and you registered your IDN long before that back at the end of 2007
Cheers - Asiaplay