This is a silly name for a discovery of mine. I call it post-modern because I take two very traditional condiments from very different cultures - Japanese 'tamari' soy sauce and Italian balsamic vinegar - and shamelessly use them together in dishes that relate to neither.
I usually find myself using about 75% tamari to 25% balsamic vinegar. It's amazingly versatile and gives a warm, rounded salt/sour and slightly sweet flavour to almost anything. It is especially good when it is cooked into a dish and reduced down and slightly caramelised with the food. Try it with mushrooms.
In a salad, I will use a greater proportion of balsamic vinegar.