Okazaki Canal in Kyoto by Heian Shrine is one of the best places to see cherry blossoms in Japan!
Okazaki Canal is a part of Lake Biwa Canal, the canal that to this day brings water to Kyoto from Lake Biwa. The most famous part of this canal is, of course, the aqueduct at Nanzen-ji Temple, but the most beautiful one during the cherry blossom season has to be Okazaki Canal.
When you get to see the vermillion bridge over the canal and the beautiful cherry blossoms, you will also get to see the huge torii gate of Heian Shrine. As a little factoid, there is actually a small door on the side of the torii from where it is possible to climb to the top, but it is for maintenance only.
Read more about the boat ride here: