You generally use a ratio of 1 unit of tsuyu to 3 units of water or stock.
What is unique about tsuyu is that it is made from 5 different dashi stocks - katsuobushi (dried skipjack), kombu, flying fish, small dried sardines and shiitake.
The combination of these flavours influences its umami taste, making it particularly rich and unique. You can really taste the sweetness of the flying fish and it adds a depth to the tsuyu, reinforcing its dashi flavour and it balances the green shiso well. It is a real feat and it is difficult to find a green shiso condiment where you can actually taste the shiso. Seafood reinforces the umami taste but also ruins the freshness of green shiso.
As already mentioned, no chemical materials or products are used. Everything is natural.
The basic ingredients commonly used to make tsuyu are liquid sugar, fermented seasoning, acidulant, etc. These are simple ingredients - sugar, mirin, brewed vinegar.
Tsuyu can be used undiluted to season salts, soy sauce for sashimi.
It makes a wonderful seasoning for grilled meat, meat and fish carpaccios, steak tartare and others. Because the green shiso is similar to basil, it goes equally well with dishes contain ing basil.
Diluted with stock it makes the perfect seasoning for soba noodles.