It's interesting how this tradition came about. An owner of an eel restaurant was complaining to his doctor friend about slow business. The friend suggested that he tell people that eating eel in summer helps you fight the heat. The marketing ploy worked and so the tradition was born.
Eel is one of my favourite Japanese dishes. The city I first lived in when I came to Japan is quite famous for their delicious eel and there it is cooked a little differently I'm told (it seems a little crunchier than other places). The small city has something like seven eel restaurants, and that's all they serve - eel on rice, the same dish but in different sizes.
The dish of eel comes with pickles and a clear soup called o-suimono. This soup is also one of my favourites, lovely and refreshing in summer. One time I was drinking the soup at the eel restaurant and found a mushroom at the bottom. Being a lover of mushrooms, I snatched it up and started chewing. "Mmm... that's a funny tasting mushroom" I remarked to my friend. She laughed and refused to tell me why until I'd finished eating it. It was actually eel liver.
So I missed the official eel eating day this year, but I think this week, I'm going to have to get me some.

Photo by Conveyor Belt Sushi