I am often asked about ponzu the umami of all sauces used throughout Japanese cuisine. To keep it simple you need to make dashi as a base, used as a base for all Japanese cuisine and fundamental to the integrity of all Japanese cuisine.

dashi: http://mesubim.com/2014/03/16/dashis-touch-taste/

Step one: dashi

Step two: add vinegar

Step three: shoyu

Step four: mirin