Rinse and pat-dry chicken parts. I used chicken drumsticks and chicken thighs. Trim off excess fats. Place the chicken parts in a large pot and add in chopped onion.

Combine light soy sauce, gochujang, chili flakes, minced garlic and sugar in a small bowl. Add into the pot of chicken and mix well. Add in the cup of water and mix well.

Turn on the heat and bring the mixture to a boil. Reduce the heat down to medium, cover and simmer for 20 minutes, stirring occasionally.

Add the potatoes into the pot and continue to simmer for another 30 to 40 minutes, stirring occasionally, until the potatoes are tender.

Scoop the chicken, potatoes and the sauce into a serving plate. Garnish with finely chopped spring onion and serve with rice.