As typical of Hiroyuki Takei while in-between large manga series, he often picks up smaller side-projects. On July 12th, 2015 a new piece of color artwork will be featured in the brochure for Kana Hanazawa’s “Blue Avenue” Concert Tour. This brochure can only be purchased at the Sendai concert at that date and will cost ¥3,000. Each venue will feature a different artist. It’s not clear if this will be the cover art for the brochure, or if an insert inside.
Kana Hanazawa was not a voice actress for the Shaman King series, so this piece of artwork is most likely not-related to this in any way. Additionally, Kana Hanazawa works under contract for Aniplex and Sony Music Entertainment (Japan). All commercially-released music from Shaman King was released through King Records’ Starchild label.
You can read more about Kana Hanazawa on Wikipedia. Here concert tour page can be found here (in Japanese).