Roughly chop the sweet potatoes into large chunks, put them in a pan with enough water to cover, add the sake, then heat over high heat.
Reduce to low heat once it comes to a boil, then add the remaining seasoning ingredients.
Simmer the sweet potatoes until tender, then serve.
User "Shunka-chan" ate the leftovers with yogurt. What a healthy idea!
Another way to eat the leftovers is to cut them up into smaller pieces and sauté them to a crisp golden-brown in butter. Sprinkle a little salt for even greater delight.
Story Behind this Recipe
I watched Japanese celebrity fortune teller Kazuko Hosoki make this on TV the other day and it looked delicious, but the only ingredient I remembered was sake, so I came up with my own version. I never used sake when stewing sweet potatoes before, so I was amazed at how it changed the favor.