This weekend I have been doing a 600-piece Victory Artistic Jig-Saw Puzzle of Oberhofen Castle. It is a donation to the charity shop, and, being a plywood puzzle, and just over 50 years old, it has some value if complete.
So I (dedicated volunteer that I am) have borrowed it to check it is complete before putting it out on the shop floor.
Text on the side of the box:
"NO GUIDE PICTURE is provided with this Gold Box VICTORY Jig Saw Puzzle. To do so would destroy much of its absorbing interest. The greatest pleasure is derived from not knowing beforehand the subject which the Puzzle will make and then to see the picture gradually form as the pieces are assembled."
I raised an eyebrow when I first read this. But it has been fine. I've had to abandon some of my normal methods, and there has been more moving of solved bits around, but it has not slowed me down appreciably. Would recommend.
I'll post a picture when it's done.