Marukameseimen

Photo: http://www.marugame-seimen.com/

Great place for you to experience real Japanese Udon for the first time. Cheap and good for its pricing. Many different kinds of Udon and Tempura availabe. Set this as your benchmark to evaluate Udon going forward. A number of branches available in Tokyo and expanding overseas as well (see below). 

My rating: 4.0

Marukameseimen (Shibuya branch)
Website | Tabelog | Domestic branches | International branches 
Phone: 03-3462-5075
Address: 2-9-9 Dogenzaka, Shibuya-ku, Tokyo 　
Access: 3-4 minutes from Shibuya station
Budget: 300 JPY or more 
Open: 
Mon-Fri: 10:30-23:30
Sat/Sun: 10:00-23:30