I only recently went to Tokyo and Osaka for an anniversary holiday. This was the third and unsuccessful attempt in locating any vintage Heuer watches on my trips to Japan... Unfortunately, all the watch stores I was able to visit didnt have much in the way of vintage Heuers but as forementioned, tonnes of Rolex's (especially Subbies). After asking several vintage and second hand watch dealers, most could not really tell me where to really look for vintage Heuers...

Unfortunately a bit far for you to travel, but there was a small store in Osaka tucked away at Shinsaibashi (just off the main shopping strip) which had majority of the vintage Rolex's in prestine, boxed with papers condition. The prices when I converted the exchange rate seemed reasonable compared to current market prices and the '100 years of Rolex' guide on the iPhone).

If you're in the Ginza area, be sure to take a stroll to the TAG Heuer Espace store. Yes it's not vintage Heuer, but the walls are covered with hallmark images which make Heuer the brand it was prior to becoming TAG Heuer.

From past searches, places that yielded more vintage Heuers than Japan was Singapore, Malaysia and Hong Kong. However, I'm rather wary of Hong Kong sellers as I have been burnt badly once.

Good luck hunting! Last but not least - any purchases you make over 10k yen is tax deductable, so have your passport handy!