Today I would like to write about "Potbelly", a popular sandwich chain in the United States. There are several stores in D.C. as well.
I like the toasty warm sandwich on the Potbelly Sandwich Shop. Every sandwich on menu is made to order.  
[How to Order]
First, choose between multigrain wheat or regular bread. Then, choose size from Originals ("regular" size) or Bigs
 (30% bigger). Either one can be ordered on "Thin Cut" bread (1/3 less 
bread).
Their toppings include: add Mayo, Mustard, Hot Peppers, Lettuce, Onion, 
Tomato, Pickle, Oil and Italian seasoning - or don't. It's up to you to 
make your sandwich the way you like it.
My preference is  Wreck, which contains salami, roast beef, turkey, ham & Swiss cheese.   
I'm sure this cafe will be a hit in Japan!