I like eating unagi in winter months cos it is much fattier, but seeing lots of pictures of unagi on the day of douyo no ushi(土用の丑) makes me crave for it too. The old building of this unagi restaurant is so gorgeous that it alone is worth a visit. Booking is absolutely necessary and although there were only two of us, we got the private room all to ourselves. Unajuu(unagi on rice in a bento box) is not cheap – a bit more than 4000yen(there is service charge) and soup is not included. But the quality is really high and I love the sauce which is not sweet like the usual kind. Location is convenient – easily accessible from Akihabara or Ochanomizu.
明神下 神田川本店 (Myoujinshita Kandagawa)
Add: 2-5-11 Soto-Kanda, Chiyoda-ku