Mix the sake, fish sauce, soy sauce, sunflower oil, sesame oil, and dried chili flakes together in a measuring jug. Put the chicken drumsticks into a large freezer bag, pour over the contents of the jug, seal the bag, place it in something like a lasagna dish (just in case the bag leaks), and leave in a cool place for 40 minutes or in the fridge for up to 1 day. When you are ready to cook, preheat the oven to 380°F and line a large, shallow oven tin with foil and, being careful not to let the bag spill out its precious juices, place the drumsticks, curved-side up, on it. If they’ve been in the fridge, let them come up to room temperature. Pour off 1⁄2 a cupful of the marinade, reserving it, pouring the scant remaining marinade onto the drumsticks. Cook in the oven for 45 minutes. While the chicken’s in the oven, pour the reserved 1⁄2 cup of marinade into a small saucepan, add the honey, and boil until it’s reduced to a sticky glaze. This will take 5–7 minutes. When the drumsticks have had their 45 minutes, test to see if they’re more or less cooked through, then carefully pour the juices that have collected in the tin into the glaze. Stir and pour over the chicken drumsticks, then place back in the oven for 10 minutes. Spoon the sticky juices over the drumsticks and roast for another 10 minutes. Remove from the oven, then spoon any glaze from the bottom of the tin over the drumsticks, and let them stand until cool enough to be eaten by hand.