Akasaka Fukinuki Takashimaya Location (赤坂 ふきぬき)
The original restaurant opened in Akasaka in 1923 and has been a flagship restaurant for unagi for decades. The Shinjuku Takashima branch has the same perfectly grilled unagi don as the original restaurant location. The unagi is served in set meals that are about ¥2,500 for lunch and a little more for dinner. You can also try the "hitsumabushi" style, which is a way to eat it in 4 parts. First, you eat it as is, then you add some seasoning such as leeks or nori, finally, you add some savory soup to make it a porridge.
Unagi Futabata is a chain restaurant with a location in the Keio Mall of Shinjuku. For about ¥3,000 you can get some very finely charcoal grilled unagi. Only eels caught in the fresh waters of Japan are used at this restaurant. There are a couple of ways that you can have your unagi done, including shiroyaki, which is grilled without the tare sauce. You can also enjoy the liver eel soup. The Unagi don is ¥2,680.
Shinjuku Unatetsu (新宿うな鐵)
The particularity of Unatetsu is that you can enjoy your eel on skewers, cooked yakitori style. Skewered, they serve the unagi in seven different styles that include different parts of the eel and either a salt seasoning or a tare sauce (soy based) seasoning. They have so many choices of Japanese sakes as well. The atmosphere is really nice too. There are some counter seats and some tatami tables. This is the perfect place to spend an evening in Shinjuku in good company.
For cheap eel skewers of good quality, this is the place to go! You can get a set of 7 for just ¥1,560. They're grilled with a good amount of tare sauce so the taste is on the strong savoury side. Kabuto is quite small with only 15 seats. What's more, it's located in the famous Omoide Yokocho side alleys. It's really nice to get the vibe of this Showa era area. You'll really feel something authentic eating there. And why not have a glass of sake while you're at it? Omoide Yokocho is a popular drinking place.
Tsukijimiyagawa Honten (つきじ宮川本廛 伊勢丹新宿店)
This restaurant with a solid reputation is located on the 7th floor of the Isetan department store. It has a relaxing atmosphere and is entirely non-smoking. You can have it served hitsumabushi or unagi don style. The restaurant boasts of using the traditional charcoal fire cooking technique and seasoning the eel with their secret tare sauce that has been used for some 120 years. Lunch prices start at ¥2,000 and dinner courses start at ¥2,376.