I made a reservation using the "auto reserve" service, which I was worried about because it was AI-based reservation and some online information said it was not possible to make a reservation, but it was done. When we visited the restaurant on the day of our visit, there was a huge line, but since we had already made a reservation, we were able to enter the restaurant without waiting in line, which was great.
The okonomiyaki had more bean sprouts and a flavor of stir-fried vegetables, but both the soba and udon were delicious. I learned that tonpei-yaki is different from Kansai's. I think it is a B-class gourmet food, so it is not extremely delicious, but it is satisfying enough.