New report from May 2024
Alright, so I finally made the trip, as Gyukatsu is booming, visiting a restaurant in Asakusa, where the (early) lunchtime wait was about 20 minutes. Gyukatsu is beef in a breaded coating. It’s like the katsu you get with curry or other dishes, but here it’s beef, and a high quality fatty cut. The gimmick is that you cook it yourself, on a hot plate, over a candle fire! Gimmick aside, it is delicious, literally as crispy as you want, with interesting sauces to go with. It is a bit cramped and the larger gaijins will feel customers brush past, however if you’ve never tried it, of course it’s recommended, especially during off peak hours. The meat is tender and melts in your mouth, if you are at a good restaurant.

a little cramped but worth it
I went further try other places that served Gyukatsu, such as in Ueno station. However, I have to say that this branch in Asakusa had more tender and tasty meat. Perhaps it was a lucky day, but it’s more likely they have a good supplier while the others give you cheaper prices for lower quality. Map location. Now here’s the video:
Earlier report from 2018

Gyukatsu near Akiba
3 Chome-8-17 Sotokanda, Tokyo 101-0021, Japan.
Nearest station Suehirocho (Ginza line)
Near Akiba, recommended by @NekoCristina, it’s famous for its pan grilled meat and may have a waiting line of 40 mins! Most popular dish is 1400yen.