Supermarkets in Tokyo and Sapporo?

I'm going to Japan and staying in both Sapporo and Tokyo(Ueno) next week. I'd like the store locations of supermarkets I can go to when I'm there. I know only of Aria in Sapporo, but that's it. Can you please help?

Department stores have great food floors in their basement.

http://foodsaketokyo.wordpress.com/2011/06/24/gotta-get-what-to-get-at...

http://foodsaketokyo.wordpress.com/2011/06/23/where-do-tokyoites-shop-...

Timely post, and here are two links above, which should answer your question about tokyo. I have been to the Kiba Ito Yokado (about two blocks from the subway) to buy a bunch of omiyage. We had nigiri sushi bento there which was excellent and a great value. There is also a donut place with a very nice green tea donut! Also a McDonalds there, if you're so inclined.