Tokyo has several regular food and antique markets throughout the city. If you’re looking for a Farmer’s Market then the most well-known—if not the largest—is the weekly farmers market held outside the United Nations University, but any of them will give you an opportunity to sample organic food from different regions of Japan. For antiques, then Oedo Antique Market is your probably your best bet.
Less regularly held markets are also listed on the events calendar, and if you’re here in late November or December it’s definitely worth visiting one of the Christmas markets in the capital.