It is a design made of hanakaku (a flower design) placed in the center of shippo (a geometrical design with circles intersecting a circular frame), and it is identical to "shippo ni hanakaku" (shippo with hanakaku) crest.
七宝の中に花角を入れたもので、七宝紋の「七宝に花角（しっぽうにはなかく）」と同一の紋である。