Watch shopping in Tokyo?

[darth_pies]

Off on a business trip to Tokyo next week for the first time. I should have a day or two at the end to see the sights and do a bit of shopping.

Was wondering if anyone knows if there's any good watch shops/streets/areas to check out?

I like my G-shocks, Seikos etc. so I was hoping to find somewhere that did some unusual Japan- or Asia-only models.

Any tips appreciated.