Not sure how this one comes off and I don't want to experiment and really screw the back up.  Now I am not talking about the battery compartment, I got that, all be it a real bugger.  I want to get the movement out so that I can clean the case.  If you look at the upper left corner of the case, a red circle marks a pin hole of sorts, not sure what that is for.  Anyway, does anybody know how this comes apart?  Is this a snap back?  A screw down back?  I do not see the typical small slot for prying off a snap back case so I am just not sure. Perhaps @andyboy or @Foxindebox  I know you guys do a lot of Seiko work.  Any help is appreciated.