Originally Posted by
FBinNY
This might be a "one key" system, which doesn't use a crank puller tool, because the removal "tool" is built in. These were popular for a while.
Yeah, that was my first thought too and the 6 mm center bolt is what Suguino used for their "Autex" system but the OP says he removed the fixing bolt so I'm not sure how he got it out without pulling the arm.