User blog comment:Xilinoc/Ch. 607 - THE MASTER/@comment-1338810-20141127151226

It seems to me that the Royal Guard have a theme of having non-sword objects for sealed Zanpakuto that, when unsealed, become more like swords (I'm thinking Senjumaru's needle and Hikifune's rice paddle are the equivalent of Kirinji's onsen water stirrer and Ichibei's brush). As opposed to the normal Shinigami, whose sealed swords transform into less-swordlike forms when released. That's clever.