Grate the small knob ginger and then squeeze about ¼ teaspoon of ginger juice out of the pulp. Add this to the 2 tablespoons sake and then set it aside.
small knob ginger, 2 tablespoons sake
Use paper towels to dry off the surface of the 450 grams salmon filets.
450 grams salmon filets
Add the 1 tablespoon potato starch to a tea strainer and dust every surface of the salmon with an even coating of potato starch.
1 tablespoon potato starch
Heat a frying pan over medium heat until it's hot, but not scorching hot. Add the 1 teaspoon vegetable oil and then the coated salmon. Fry the salmon undisturbed until it's cooked about ⅓ of the way up one side.
1 teaspoon vegetable oil
Flip the salmon over and then fry it until it is cooked about ⅓ of the way through on the other side.
Remove the salmon from the pan, and use a paper towel and tongs to wipe out all of the oil.
Add the sake, 2 tablespoons soy sauce, and 2 tablespoons evaporated cane sugar to the pan and stir until the sugar is dissolved and the mixture is boiling.
2 tablespoons soy sauce, 2 tablespoons evaporated cane sugar, 2 tablespoons sake
Return the salmon to the pan and repeatedly flip the salmon until it is glazed in a thick layer of shiny sauce.
Serve the salmon teriyaki over rice with any remaining sauce drizzled over it.