Udagawa
Well known, traditional Tonkatsu restaurant that has a long history. Interestingly, its Tonkatsu sandwich (to go) is more popular/recognized than its Tonkatsu to eat in there. I also never sat in and had Tonkatsu there, but rather called them up for a Tonkatsu sandwich to go (we call it "Katsu-sand" in general) a few times. Reading others' reviews in Tabelog, I get a feeling that the Katsu-sand is the one you want to keep focusing on.
If you just want one package, call them for it at least 20-30 minutes before you get there to pick up. Considering its portion It could be a meal, or a snack for 2 people. Not cheap, but worth a try if you like Katsu-sand.
My rating: 4.5
Udagawa
Tabelog | 03-3241-4574
Address: 1-4-15 Nihonbashi-Honcho, Chuo-ku, Tokyo
Access: 3 minutes from Mitsukoshimae station, 8 minutes from Ningyocho station
Budget: 1,800 JPY
Open: 11:00-13:50, 17:00-20:30 (Sat 11:00-13:50)
Closed: Sunday, Holiday