Great find!
The rooms are small but perfectly adequate and spotless (as are all other spaces), the staff is extremely friendly and helpful, and the breakfast is great value and delicious.
While it's not central it is very near a station on the Hibiya line, so getting around was never a problem. The neighbourhood is quiet, which was actually welcome after spending the day in the hustle and bustle.
As for amenities - the jacuzzi on the top floor is a nice end to the day. And the tea ceremony, also open to non-guests, was very special - insightful and fun.
Would definitely recommend it and go back.

We loved Andon - we stayed on two occasions a couple of years ago, and absolutely loved it.

Location-wise it's a little off, but it is in a nice quiet residential area, and we appreciated staying in a neighborhood where people actually live. It's also a short trip away from Ueno, which is a good major hub to be close to with shops and markets and restaurants and parks and temples - just about everything you'd need.

Staff was extremely helpful and the whole place is very traveler/backpacker friendly and welcoming. Breakfast is great, and there's tea available all day. Rooms are TINY (you can touch both walls at the same time if you stretch your arms), and rather cold, but duvets are LOVELY. Make sure you take part in the on site tea ceremony, and do book the upstairs sento bath (hot tub), but beware, it's VERY hot.

If you want to experience Japan and meet other travelers, there is no better place than Andon to do so.

The Andon Ryokan is an inexpensive yet unusual hotel in Taito, Tokyo. Hidden in a quiet residential street just a short walk from Minowa Station the innovative and modern Andon Ryokan is instantly recognisable amongst the hotchpotch of modern concrete towers and old-fashioned wooden structures that surround it. Conceived from the idea of creating traditional Japanese features in modern materials, the hotel was designed by architect Irie Masayuki and featured in a 2005 Architectural Institute of Japan journal. An opaque glass facade, representative of shoji screens, covers the front of the building while metal panels and louvres replace a traditional wooden framework. Just like the paper lantern that the ryokan takes its name from the whole hotel is illuminated at night as guest room lights shine through the translucent green glass. Inside the hotel's sleek black walls, narrow corridors and concrete floors border on the industrial but are interrupted by alcoves filled with brightly coloured Japanese antiques ...

Read more at:
http://itsumojapan.blogspot.com/2011/06/review-andon-ryokan-tokyo.html

I stayed at Andon Ryokan with my husband for 4 nights during our honeymoon and I was extremely impressed. The room was very comfortable and the staff was so nice. They helped us plan out our activities each day and had great suggestions. They made us breakfast fresh each morning, and the cinnamon french toast was delicious! We had a great time being taught origami one night, and the location was great too. I guess the only drawback would be that we didn't have our own bathroom and had to use the public one. But there was a fabulous jacuzzi in the basement! I would definitely recommend Andon!