Used to enjoy this place as it's close by, serves decent tonkotsu ramen, and not busily packed with guests. Now that I've been here a couple of times, I kind of understand the reason why.
They have recently updated their menu to serve more variety of soup base and topings. We ordered a mushroom cream ramen, and the both tastes a little like cream of mushroom soup. The portion is decent, soup is hot, comes with a ramen egg. But that's about it. For the price they charge (~$14 per bowl), it is nothing out of the ordinary. With all the competition in town and all kinds of ramen joints popping up, I don't see what makes Tohenboku unique.
Furthermore, although my family don't normally dwell around the restaurant to chat and mingle, the staff seemed to have rushed us to take our bowls away and offered us the bill even before one of us were done.
Probably would opt for other ramen joints in the future.