The One Piece anime has plenty of similarities with its fellow Big Three shonen titles Naruto and Bleach, such as having an action-oriented hero who embraces the power of friendship to save the innocent and defeat great evil. Monkey D. Luffy, the series' protagonist, has trained hard and learned a lot from his many fights on the high seas, but he isn't exactly the same as the other protagonists seen in shonen's most popular series. Luffy's approach to power scaling is remarkably different from Naruto's and Ichigo's, even if the results are generally similar.
Source：https://www.cbr.com/why-one-piece-has-few-training-arcs/
