On the packaging, look for "Made in Japan". The 50 packs at least come in the usual TY cakebox (have a look at the TY FAQ sticky for details of the spindle/cakebox).
I mention the 50 packs, as I have had 25 packs of the 8x Verb +R that had a regular cakebox with grey bottom, but all the 50 packs I've had, have had the TY cakebox.
I'm guessing you're in Europe, right? 'Cos if you're in North America, you won't find the TY Verbies
Edit: Additional info - I find all mine in Staples/PC World, but SVP online have the 16x Verb TYs, too.