User blog comment:Xilinoc/Ch. 639 - BABY,HOLD YOUR HAND 2/@comment-2120712-20150820081922

Bankai Name: "Konjiki Ashisogi Jizou: Matai Fukuin Shoutai", meaning "Golden Leg-cutting Ksitigarbha: Diseased Body of the Fuku Seal of the Demonic Fetus".

The "fuku seal" is the symbol written on Jizou's belly there. It's likely some obscure name for a mudra, possibly either one of Jizou's usual mudras.

Fuku could translate into crawl.

Credit to Andygoesrawr on reddit.