Begin by heating a dry skillet over medium heat. Add the white sesame seeds, stirring constantly for about 3–5 minutes until they are golden brown and fragrant. Be vigilant to prevent burning; the seeds should be slightly darker but not charred. Once toasted, remove them from the skillet and set aside to cool.

In a mixing bowl, combine the unseasoned rice wine vinegar, soy sauce, roasted sesame oil, neutral flavored vegetable oil, brown sugar, and finely minced ginger. Whisk the mixture vigorously for about 1–2 minutes until the brown sugar is fully dissolved and the ingredients are well incorporated. The dressing should be smooth and combined.

Once the sesame seeds have cooled, add them to the whisked mixture. Stir well to ensure the toasted seeds are evenly distributed throughout the sauce.

Take a moment to taste the sauce and adjust the seasoning according to your preference. You might find that adding a splash more vinegar for acidity or a pinch more sugar for sweetness enhances the overall flavor.

Once the seasoning is to your liking, transfer your Japanese sesame sauce into an airtight jar. Seal it tightly and place it in the refrigerator, where it will keep fresh for up to one week.