Yoshinoya

In the Gyudon world their are three main competitors in Japan. Yoshinoya, Sukiya, andMatsuya. 

By far the most renowned establishment in Japan is Yoshinoya. It is easy to see why Japanese love this particular chain so much. 

Currently the regular sized Gyudon (Nami de) is priced at Y380. You can't beat this price per portion size anywhere else in Japan. 

The menu is simple and the price is even more modest than the other two competitors. AlthoughYoshinoya does not offer the same variety of food as Matsuya and Sukiya, you can order yourGyudon with extra sauce at no extra cost. 

A Japanese person taught me the linguistic command which sounds something like (Toi-YoDaku).

But as with most interactions in Japanese, you'll probably have to repeat it several times until they understand what you mean. 

Trust me, if you order this successfully, you're in for a real treat.