Cut Satsumaimo into 1" (2cm) thick rounds. Soak in water for 5 minutes.

In a pot put Satsumaimo and add water to cover the potatoes. Let the water boil and strain right away.

Put the 1 1/2 cup water, sugar and salt in a pot and stir, then add potatoes back. At medium heat cook until the sauce boils, turn the heat down to low, cover with parchment paper, and cook about 20 minutes.

Cool leaving potatoes in syrup.