After a phenomenal run of 15 years Naruto has ended and of course that entails a plethora of new interviews with Kishimoto-sensei. Japan's Asahi Shimbun has run a interview with Kishimoto and talks about the impact Naruto has had. They describe Naruto as one of the driving forces behinds Jumps popularity, noting that global sales were over 200 million copies as of September.
When asked about Narutos overseas popularity Kishimoto had this to say.
Because manga artists are always working inside rooms, it is difficult for us to see firsthand if our works are really popular. It was not until I received many fan letters from overseas that I realized (“Naruto” is) popular outside Japan. Some of those letters are written in languages I do not know, so I understand that my work is read by people in various countries.The article also took time to ask about One piece.
Q: Were you conscious of “One Piece”?
A: It is impossible to be unconscious. (Both “Naruto” and “One Piece”) are serialized in the same magazine, and “One Piece” has always been running ahead of the pack. I have been able to work so hard writing “Naruto” thanks to “One Piece.”
Go read the whole article it is fascinating.