There are different ways to make meatballs, a.k.a. Tsukune. The meatballs are prepared like most meatballs, minced meat. Now if you have time, take a look at the internet and pictures of yakitori meatballs. Most if not all have a charred look and that is the difference here. This chef is careful in his preparation not to use, tare, pronounced like the word “tar” and “eh”, just like the Canadians say.
The tare is a sauce many yakitori chefs use to sweeten the meat prior to grilling. If you have the experience, you will see many chefs dip the meat into a sauce prior to grilling. The tare is very sweet made of mirin, sugars, shoyu and sake and or dashi based. It is not my style and I prefer it salted; see the difference for a clean taste.