Nami's hair and face are recognizably similar to her final design, although she appears to have pigtails rather than the short hair she possessed in her first appearances.
The ax is also wrapped in a very heavy looking chain, and from blade to handle is nearly as tall as she is. The concept art for Nami in Color Walk 1 depicts her with an absolutely massive battleax, giving her a real berserker-type vibe that strikes quite a contrast with the staff and weather magic she'd eventually come to be known for. Related: Luffy's One Piece Adventure Nears Completion According to Creator Some of the concept art included provides a peek at a very early Nami who couldn't be more different than her final design. One Piece: Color Walk 1 is one of the rare artbooks that was released outside of Japan, receiving a translation by Viz in 2012, almost a decade after the book was first released.
These artbooks typically include reference sheets, style guides, insight from the animators or artists, and most interestingly, concept art from before the characters became as well defined as they are upon release.
A HAT IN TIME CONCEPT ART SERIES
It's not uncommon for popular anime and manga series to release artbooks, most of which never see translation or release outside of Japan. The most radical changes in character design, however, are from before the series was even released. As one of the longest-running manga series on the market, One Piece has gone through many design shifts in art and style for its characters over the years.