Mashiki is located in the Kumamoto Prefecture, which is where One Piece author Eiichiro Oda is from. The prefecture experienced a series of strong earthquakes in 2016, and both of these localized phenomena swirled together to inspire a newly erected Sanji statue.
Sanji now stands proudly in support of Kumamoto. It’s very appropriate, too, because the school lunch center in Mashiki-cho was damaged by the disasters and was unable to serve hot meals at the time. Thus, Sanji, the go-to chef of the Straw Hats, was chosen.
It’s all part of a greater reconstruction project. The mayor commented on the statue, saying Sanji gives him “courage and hope” during the process.