In Minnesota, it's very difficult to overwinter plants outdoors in containers. This might especially be true for your Japanese Maple if it is a variety that is rated for growing zone 5. If this is true, the tree will not survive the winter outside. If you have a maple rated for growing zones 3 or 4, the survival prospects are slightly better. However, see the following two publications about how even such varieties may experience difficulty being outside over the winter.

https://www.gardeningknowhow.com/garden-how-to/gardening-by-zone/zone-3/japanese-maples-for-zone-3.htm

https://www.gardeningknowhow.com/garden-how-to/gardening-by-zone/zone-4/zone-4-japanese-maples.htm

As these publications suggest, putting your pot into the ground would be better than leaving it above ground. Unfortunately given our recent night temperatures, frozen ground may preclude this route. You then should consider moving the pot inside to an unheated place that will remain above freezing during the winter. The goal would be to maintain a relatively constant soil temperature in the pot and avoid freeze/thaw cycles. The following three publications will elaborate on this point:

https://www.bbg.org/gardening/article/overwintering_potted_plants

http://planttalk.colostate.edu/topics/miscellaneous/2028-overwintering-container-plants/

https://www.extension.iastate.edu/osceola/sites/http://www.extension.iastate.edu/files/osceola/October%2015%20Overwintering%20Potted%20Plants.pdf

We believe that the bottom line is that either burying your pot or bringing it indoors are your two best alternatives.

Good Luck!!