Two paragraphs might do it. Spoilers ahead so you were warned. This should be renamed Baki - A day in the life of Orochi Doppo. It shows Doppo way before he got his scars. This may seem to not make sense according to the original Baki but I thought about it this is where he first meets Yujiro on the streets before he opened a dojo; I remember him saying something along the lines of "Oh it's you" and then he got the scars in a bar after he opened his dojo. So things do line up a bit.
These stories aren't necessary nor do they add to the world of Baki, it is 5 chapters that focus on a specific character. The only story which was good was his fighting tiger one which I was surprised they didn't do in the original story but whatever. Like my score shows it's about average, only read once and never look at it again.