Take a bowl. Put red bean curd in it and mash until the curd turns smooth.
Add soybean paste and garlic to the bowl and mix everything well.
Then, add sugar, vinegar, and chili sauce and stir everything to combine.
Add water gradually to the sauce until you achieve the desired consistency.
Let the sauce cook over a low heat for 3 to 5 minutes.
Taste the sauce. Adjust its sweetness, sourness, or spiciness if needed.
Let the sauce cool down. Then transfer it to an airtight glass container.