Boil the potatoes. If using bacon, soak in hot water for a short time. If using frozen bacon, microwave in the refrigerator. Throw away the liquid.
Cut and prepare the edamame and bacon. If you really want a bright color for the edamame, set 1/3 aside and mix them in at the end.
Once the potatoes have boiled, drain the water. Return them to the same unwashed pot. The excess moisture will evaporate. Don't turn on the heat.
Mash the potatoes in the pot.
Once they have cooled, season with salt and pepper. Add the edamame and bacon, and stir them in. Add the mayonnaise and mix.
Serve on a dish and it's done.
And another user made a variation using Japanese mustard mayo. Be careful not to add too much.