This is a bit of a Moby Dick for me. There is this candy, Gingerbon, that that has a very tough (for lack of a better word) chew to them. The texture is like a very chewy taffy that sticks to the nooks in your molars. However, it's resilient enough to not deform under moderate pressure.
The ingredients, listed in order, are simply sugar, tapioca starch, ginger, and vegetable oil.
I suspect the vegetable oil is used as a releasing agent for whatever mold is being used. This is simply based on the idea that the ingredients are listed in order of prominence but, since this is a candy made overseas, the order might not indicate anything.
The candy is mfg'd in Indonesia. I looked it up and found Permen Jahe but the recipes online seem to make something more akin to a gritty tootsie roll.
The only other potential candy that might resemble this in the States is Gin Gins (formerly known as Ginger Chews) by Ginger People. They only list 3 ingredients (no oil).
I'm not 100% sure on this but I believe starch gelatinization breaks down well before the soft-ball stage of sugar so boiling them together at the same time doesn't seem like the best option. Adding it towards the ends seems like a it would just make something akin to twizzlers since, again, it wouldn't have enough water to gelatinize. Adding a slurry of gelatinized tapioca to hot sugar seems like a recipe for disaster...
I would love to experiment but I don't really have the resources for it. Is there another way to get chewy candy with just starch and sugar?