Heat the sesame oil on medium heat until it begins to shimmer.
Add the grated ginger and saute until fragrant, 20 to 30 seconds, stirring constantly.
Add the honey and cook until it melts.
Pour the soy sauce and vinegar into the pot and turn the heat up to medium-high.
Cook the mixture on medium-high, stirring every few minutes, until it reaches your preferred thickness.
After about 15 minutes, you should notice the texture changing. If you want a thin sauce or glaze, you’re good to go now.
If you continue cooking the sauce, in about 5 more minutes, you’ll see that it gets noticeably more thick and bubbly. See the picture for what the sauce should look like at this stage.
At this point, if you dip a spoon in it and run your finger through the sauce (be careful not to burn yourself!), your finger will leave a trail that doesn’t fill in. For most uses, I’d suggest you take the sauce off the heat at this stage. (Notice the spoon is thinly coated and the finger trail doesn't fill in.)
If you want a very thick, sticky sauce, continue cooking the mixture for about 5 more minutes. At this point, it will have much less steam and be visibly darker and thicker as it bubbles. Notice the difference between this picture and the previous one of the bubbling sauce.
The back-of-the-spoon test at this stage will have a visibly thicker coating. Notice the thicker layer on this spoon. DO NOT cook the sauce further than this stage or it will be unusably thick.