In Yamazaki's Lunch Pack series, they now have an offering based on Otaru Ankake Yakisoba 小樽あんかけ焼そば, which is a local specialty of the Hokkaido port city Otaru. Ankake yakisoba is buckwheat noodle based chow mien noodles with a starch based topping. It is considered a "soul food" of the area and there is an organization called the Otaru Ankake Yakisoba Shineitai 小樽あんかけ焼そば親衛隊 organized to protect and promote this dish. It is this organization that collaborated with Yamazaki on the development of this product. Comments on the website complement the authentic sauce. From what I can tell, there are many varities of this specialty, but the defining element appears to be the use of local seafood. ヤマザキ ランチパック
Photo is a web capture for explanatory purposes, copyright belongs to the company.