There are lots of summer festivals and events all around Japan, and in Kyoto especially with Kyo no Tanabata, the fireworks in nearby Otsu city and, of course, the Bon Odori just like in the rest of Japan. There is one festival however, that is unique to Kyoto and happens every August, and it’s known as the Daimonji or Daimonji Yaki festival (which basically can be translated to “large letter festival”).
Held every year around mid-August as a way to end the Obon festival, the Daimonji involves the lighting of huge fires in five locations in the mountains that surround Kyoto city. Each of the fires is built in the shape of a Kanji character (or in one particular case a boat!). The first of the fires to be lit is “Dai” on Daimonji mountain itself. This is the character for “big” or “great” and is always lit at 8 pm. Over the next half hour the remaining four fires are lit, and generally last for about half an hour so for a while it is possible to see all 5 at once from certain vantage points in Kyoto.
There are other fires too, one in the shape of “big”(大), the character for “wondrous dharma”（妙法）, one that looks a torii gate such as you’d find outside a shinto shrine, and one more that is simply in the shape of a boat.
It’s quite difficult to get a spot where you can see all of the fires at once, it’s possible from Kyoto tower, and a few hotels have viewing events so you can buy tickets to see them, but most people simply find a spot where they see one or two of the fires from. The most popular spot is along the Kamogawa river north of Sanjo station. If you go there to watch, you will see big crowds of people, mostly dressed in Yukatas and enjoying some drinks during the warm summer night! There are some great traditions around the daimonji too such as if you manage to catch the reflection of the fires in your sake cup and make a wish, if you drink it your wish will come true!
The Daimonji fires don’t last a long time but it’s usually the start of a great night as there’s lots of people out evening the night after seeing the fires so the riverside and the nearby bars and clubs are all full of people!