sakuramon
The sakuramon (桜紋) is a stylized depiction of a five-petaled cherry blossom. The tips of the petals often feature an indent.
It is notably used on rank and cap badges of the Imperial Japanese Navy and all branches of the Japan Self-Defense Forces. It frequently shows up in copyrights with a naval theme. In Azur Lane it's used as the emblem of the Sakura Empire and appears on many of that nation's characters. It's also seen on several Kantai Collection characters, where it is often mistaken for a kikumon.