Board Thread:General Discussion/@comment-1429792-20140920205950/@comment-24282510-20140923180940

Even without the use of 99.99% of his powers Isshin could still have made it, before his powers were sealed but he never finished it. And over time managed to put what little finishing touches he needed to before the Kon/GF event. And didn't Isshin say his powers were awaken somewhat but not very much after his wife/Ichigo's mom died. Huh not really in the feel to look that up. But it was somewhat between 528 and 537.

Maybe to sell it in SS in a shop to people has protection from hollows or has a project or test for his captaincy.

And who is to say it uses his power to make the field? Could be Kon's/anyone that is in danger.