Walking through Shibuya, I stopped in front of a big sign that read “Yakiniku · Kasu Udon.” Udon at a barbecue place? I was too curious not to go in.

What is Ryu-no-Su?
It’s a yakiniku restaurant that also runs a wholesale meat business, serving mainly Yamagata beef. According to the greeting on the menu, they skip the usual yakiniku staples like reimen and bibimbap.
Instead, their signature is kasu udon, made with abura-kasu: beef intestine slowly fried until crispy. They love it so much they built their own factory to make it. They also welcome guests who come in just for a bowl of udon, which is exactly what I did.

What’s kasu udon?
It’s a regional dish from the Osaka area. The crispy abura-kasu releases a rich, savory fat into the broth, so it tastes nothing like the light udon you might be used to.
What I ordered: Aka Kasu Udon + extra beef
I had the spicy Aka (Red) Kasu Udon (¥1,100) and added the beef topping (¥350), ¥1,450 in total. The broth was rich, a little sweet, and about as spicy as Korean gochujang: warm, not painful.
The extra beef was worth it, with tender slices coming up in almost every bite. The noodles were thick and chewy, and I ended up drinking almost all of the soup (the last photo proves it).





Other options
- Specialty Kasu Udon ¥900
- Beef Kasu Udon ¥1,250
- Stamina Kasu Udon ¥1,450
- The everything-on-top Home Run Kasu Udon ¥2,650
- You can ask for a smaller portion of noodles.
- They also serve Yamagata beef yakiniku, offal and kasu motsu hot pot.

Good to know
- The restaurant is cashless only: cards and IC transit cards are accepted.
- The walls are covered with business cards, banknotes and photos left by guests from all over the world.
- Every counter seat has its own grill, so it works for solo yakiniku too.

Info
Prices are as of my visit.
Ryu-no-Su Shibuya Honten
Address: 1F–2F, 36-3 Udagawacho, Shibuya-ku, Tokyo 150-0042
Hours: Open 24 hours, so it works for a late-night udon craving too.




















































