I'm a big fan of Ming Tsai and found this at ming.com. Sounds interesting! He says:
This vinegar reduction, which adds intriguing sweet-tart flavor to dishes, takes advantage of the fact that when balsamic vinegar is cooked down, its inherent sweetness is intensified. Three-Vinegar Syrup combines the complex flavors of balsamic, rice wine, and Chinese black vinegars. It does wonders for beef and seafood, but it can also be used to intensify the taste and aroma of sweet foods including fruit, or as a dessert sauce; I serve it over vanilla ice cream with great success. And because it is syrupy, you can use it decoratively, too, to beautify plates while adding a flavor accent.