Roger D is an enigmatic German (?) manufacturer and creator of a number of unique, instantly recognisable puzzles. They only ever appear in small quantities and the usual shops tend to sporadically have a few of them in stock and sell out fairly quickly. When they appear on auctions they’re invariably hunted down while their prices are chased up by collectors wanting to add to their hoards.
Roger is by all accounts a bit of a mystery, even to some of those who sell his products, with several of them dealing through middlemen who refuse to allow any direct contact with the man himself. One anecdotal story involves a series of communications backwards and forwards through a middleman about a particularly nice puzzle, enquiring about possibly stocking it regularly, pricing and such, until the vendor asked for about thirty puzzles to stock-up, at which point all communications ceased … moral of the story: if you like Roger puzzles, and you can find one or two, buy them! There’s no telling when you’re likely to find them available again.
A huge part of their charm is that they don’t come with any instructions – or solutions, so the first challenge is usually working out what the object of the puzzle is, and sometimes that’s far from obvious.
Schleussel was the first Roger D puzzle I stumbled across – at the time I didn’t even realise it was a Roger – I just bought it from
Grand Illusions as a fun puzzle lock. I’ve done a lot of surfing, err, research, since then so I’d like to think that I’m more likely to recognise a Roger puzzle these days, FWIW.

Schleussel, or ‘Key’ if you’re Anglo-ish is a pretty simple looking lock and key, so your first assumption is (OK mine was!) it’s some form of puzzle lock, put the key in the lock and turn (‘cos that’s what you do when faced with a lock and a key, isn’t it?) – things go well at first, it turns almost a full turn before stopping … OK, so what’s the next thing you do? Turn it back, yeah? … right about now, you realise that Roger’s backed you into a corner and you’re stuck there – damn key won’t budge – so now you know, the puzzle isn’t putting the key in, that’s easy, it’s not turning the key, that’s also easy, it’s getting the damn key back out again – ‘cos it’s stuck in there now!
A bit of fiddling will generally get it back a bit, but as with good puzzles, one slip up and you’re back to the start again – except that in this case, the start has the key firmly locked in place at the extreme of its travel. Not helpful … but nice for a puzzle!
Without giving too much away, my first solution wasn’t particularly elegant, but it worked, was repeatable and didn’t take very long – but it looked like a kludge … several months later I was thinking about the mechanism and wondered to myself if there might be a far more elegant solution, and indeed there is: it opens in seconds, every time, with one smooth movement … now I think I’ve solved it properly.