Add all the ingredients to the pot. Make sure that at least ¾ of each chicken thigh is submerged in the sauce. If not, your pot is too large.
Bring to the boil on medium or medium-high heat, stirring for the sugar to dissolve. Don't use high heat as you don't want to shock your chicken and make the meat contract and be tough. (I used heat of 7 on a Bosch induction stove with a maximum fire of 9)
Once it's boiling, turn down to medium or low heat so that the sauce is at a simmer, uncovered i.e. you see tiny bubbles rising to the top of the sauce. Let it simmer for 20-35 minutes, depending on the size of the thighs. Note after some time, the sauce may end up hot enough and start boiling, so you may want to adjust the heat down. I started with the fire at 5 (Bosch induction stove, maximum 9) and eventually reduced to 2.5-3.
After 20-35 minutes have passed, flip the chicken and simmer for 10 minutes more then test for doneness- juices should run clear when the thickest part is sliced. I like to slice from underneath so the skin isn't cut and the thighs remain presentable.
If not done, return to the pot to simmer a bit more.
If done, remove all the thighs from the pot even if you're not eating them immediately (you don't want them to continue cooking in the pot). Optional glazing with a little oil if you want a glossier skin. Serve with rice or noodles. Stir the sauce before ladling a bit over the rice or noodles. (Taste first as the sauce can be salty though the chicken is perfectly seasoned.)
I recommend keeping the braising sauce as master sauce- sieve and store in fridge for 3 days or freeze it. There are recipes ideas in the post regarding what to do with the sauce!