Where can I get authentic ingredients?

Dana :)

Lee Kum Kee has a ton of ingredients I use often and is usually accessible at grocery stores - including hoisin and oyster sauce as well as dark soy sauce. I generally use kikkoman for soy sauce (although I like to try the ones made in Japans!). For Rice Vinegar, I honestly buy whatever's available, as long as it's unseasoned. Some more specialty things like black vinegar, Shaoxing cooking wine, broad bean paste, or sichuan peppercorns, I confess I go to Amazon and pick from what's reviewed well. Or if I can find those at a Chinese grocery store I'll buy what looks like a popular brand! Also, not traditional ingredient, but I like Fly By Jing chili crisp! (can buy online).

Lily C

Authentic is really defined by what region of Chinese food you're cooking! Dana is absolutely right, Lee Kum Kee is a generally a solid brand, but i associate that more with Cantonese / Taiwanese flavors. For example, if you are making Sichuan/Szechuan food, look for ingredients that are made in that region, etc.