I did and interview with a local chef recently that was using shio koji (fermented rice) as both a seasoning and as a marinade on some of his new dishes.

He said it was pretty popular in japan right now.

He used it as a marinade on some ribs and also added it to a sauce for his milk udon.

Koji ribs

Here is a video of the interview I did. In it he talks a little on how he uses it.

I guess I will need to look for it the next time I go to the Asian market to give it a try.