Soy sauce In het nederlands
This is another of the range of salted, fermented saya bean products developed over millennia in Southeast Asia.
It is not thai, but is widely used in Thailand in Chinese-style dishes.
There is an essential distinction between light soy and dark soy sauce, light being saltier and dark sweeter (though still pretty salt).
Chinese soy sauces are easily obtainable; so is the Japanese brand leader, Kikkoman, which is really a dark soy but can be used in any recipe that calls for soy sauce. Japanese soy sauces, also called shoyo or tamari, are healthy in that they are generally additive-free.