That'd be awesome... her Shikai is named Itegumo (凍雲, "Frozen Cloud"; Viz "Frozen Snow").
It could be Mirrors... however, given that the weapon becomes a standard Katana, but with two blades protruding from the hilt a 45 degree angles... if it is a Shield.... I'd wager the sword creates ice onto it between those blade extensions to widen the blade into a shieldish deal.
Alternatively... it could be something like Harribel where it shoots Ice spears (instead of water/reitsu). Having the ice blade shoot from that gap between the blade extensions.... one could say it is like the Ice running across the length of the blade which matches her activation word which is Run.
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