He set up a series of dummies around him and proceided to visualize that there were some form of opponent. He set about, first looking with just his eyes to see what the best course of attack would be, then went about with just pure feeling, as he found no way to deal with so many, at the same time.
Spinning around, he cut, slashed threw the dummies, but each time there just seemed to be somthing missing. He just felt that if this were a real combat, he would be missing the ones behind him.
Focusing hard for a few minutes he tried to feel the presence of the dummy, and when that did not work (for it gave of no trace of spirit pressure) he just make a image of how it was, the did a fairly basic spin, slashing the ones infront of him, turning then thrusting out getting the few that were behind him leaving just the two to the sides. a series of thrusts got rid of the one infront of him and he spun and kicked the last one, to finish it off.
Feeling tired he sheathed his Zanpakuto and called it a day, then walked over to the doors and walked out of the dojo.