This sandwich is a teriaki sauce and mayonaise hamburger sandwich. I have tried it and it is pretty good and very affordable at 175 yen (if I remember correctly). I am translating this as hamburger, but usually many people would argue that it should be the word for chopped beef (hamburg in Japanese). However, since this is on bread, it seems appropriate to use hamburger (hambaga in Japanese). ヤマザキ ランチパック ハンバーグ
Photo is a web capture for explanatory purposes, copyright belongs to the company.