Watercolor supplies in Tokyo/Osaka/Kyoto?

Hi!

I'm planning on travelling to Japan in a couple of weeks with my family and my personal main goal is to find authentic watercoloring supplies. I don't need brands that can be found in the U.S. and would rather find traditional Japanese brushes and paints. Are there any shops you can recommend that are like this? They don't necessarily have to be within Tokyo/Osaka/Kyoto.

Thank you!

Visit Tokyu Hnads(Tokyo/Kyoto/Osaka) craft and/or stationary section.

If you are in Tokyo, I recommend you to visit "Sekaido" in Shinjuku head store for both professional and hobby use. And also, Sekaido is cheap. The most products there can be discounted for 20% for non-members, 24% for members.
"Sekaido" Shinjuku head store
3-1-1 Shinjuku, Shinjuku-ku
Tokyo 160-0022
open 9:30-21:00 7 days a week
watercolor paints and brushes are on the 3rd floor.

I especially like shops
Gekkoso
http://www.timeout.jp/en/tokyo/venue/17360/Gekkoso
In other
Sekai-do head office (cheap and varied)
http://www.timeout.jp/en/tokyo/venue/21905
Shibuya uematsu (especially many Japanese paintings of paint)
http://www.timeout.jp/ja/tokyo/venue/11536
(Per next to the Shibuya Hikarie)
Other is
Tokyu Hands
http://www.tokyu-hands.co.jp/foreign.html
Ito-ya
http://www.ito-ya.co.jp/
These are the stationery store, but also sells general art supplies.