Steps
In a small saucepan, combine sugar, rice vinegar, soy sauce, minced garlic, grated ginger, and water.
Heat over medium heat until the mixture starts to simmer.
In a small bowl, mix cornstarch with a little water to create a slurry.
Add the cornstarch slurry to the sauce, stirring continuously until it thickens.
Remove from heat and stir in sesame oil and ketchup.
Let it cool before packaging into sachets.