This is nothing like the ketchup that you’ve come to know and love (or loathe); this is an authentic recipe for the english precursor. Originally, ketchup was a wide variety of thin savory sauces inspired by soy sauce, fish sauce and other delights the English found in Asia. Trying to replicate them with local ingredients, like green walnuts or mushrooms, they’re full of flavour and add a savory kick to meat, rice and soups. (Worchestershire sauce is a closer comparison than modern tomato ketchup.)
Try it, and be delighted with this taste from the past!