For this example let's say you are selling a baseball hat and in your store you have several categories that the hat belongs to, such as athletic wear, hats, and summer clothing.
Let's also say that when someone clicks on the hat you always want your breadcrumbs to reflect the hats category rather then the athletic wear or summer clothing.
Normally in Miva Merchant when a customer opens a category in the store and then clicks through to a product, the breadcrumbs will always show the categories the customer clicked in from. If they were in the athletic wear category and click on the baseball hat, the breadcrumbs will reflect athletic wear.
The way to make it so baseball hats always reflect the hats category is to set a Canonical Category.
Open the product in the Miva Merchant admin.
Assign the "master category" (for this example "hats") to the Canonical Category field.
If you don't know the category code, click the "LOOK UP" button (note that I selected "Category 2" below, but it is the same process if I were to select "hats".)
That's all there is to it. If you set the canonical category for a product, every time someone visits that product it will always show the canonical category in the breadcrumbs as well as in the meta and SEO information if you have it set up that way.