Chayote is NOT originally from Korea. In fact, I’ve never seen it when I used to live there. But it is a common vegetable in latin America and you can find them in most ethnic/ asian markets in United States. It kind of looks like a deformed melon/apple/pear that I never thought of eating it until my mom’s friend gave us a jar of chayote pickle that she had made. Next thing we knew, we were pickling a whole box of this stuff because it was the best pickle ever!!
The recipe can vary depending on how spicy you want it to be. If you don’t like spicy food, you can eliminate Jalapeno pepper and just put more chayote or onions in. Experiment and find the right ratio that you like the best, but the soy sauce and vinegar should stay the same to make it a pickle.