For the kimchi, cut radish into small cuboids of 1-2cm edge length. Place in a bowl with salt and allow to drain at normal room temperature for about 3 hours. (Alternatively, you can use Chinese cabbage instead of radish).
Then lightly rinse the radish (a tiny bit of the salt should remain).
Mix a paste of coarsely ground hot Korean chili spice (gochu-garu), a tiny bit of ginger, enough fresh juicy garlic, 1 grated onion, chopped young onion and (optional, if desired) fish sauce. Mix well with the radish.
Put the radish in canning jars, seal well and leave in a warm room for 1/2 to 1 day at the beginning. Then leave to infuse in the cellar for a few days and finally in the icebox if desired. Do not open before 2-3 days.
The aging process is very dependent on the individual flavor you want to exhibit: if you want a ‘raw’/salty tasting kimchi, 3 days of aging is recommended. If you want a sour kimchi, it should be a little longer (up to 5 days out of the refrigerator).