I don't know if this question constitutes a home improvement or life hack but I'll ask here first. We live downstairs for my wife's parents in Japan. My wife's mother occasional invades downstairs. She changes around things- this infuriates my somewhat control-freak wife. Is there a device that I buy on the internet that allow a sliding door to be locked? Its a double sliding door with no internals of Japanese design- more robust that those paper doors but essential light weight wood on the wood runner with no bearings. I need non-permanent- no modifications to either door or wall. Just need to provide some resistance to entry. Its an internal door. Because there are two sliding doors- I envision perhaps a Z connection- A L with an end- the gap between the doors is 5mm- and small lock to lock the doors together. Have you seen something like that? We have a decent a hardware store at last near home but no tools.
I'm assuming you want the door to be locked from the outside and when you are not home? Here are some items that should have the type and style you would find appropriate for your home: keyed sliding door handles .
The Z would do it & you might find just the top portion of an over door hanger would work, there are several here
Other than that, you might try L-brackets tied together will do the trick. These are perfect for a wing-nut screw together & your hardware store might customize them
Just wrap the contact points with a rubberized tape to avoid door marks.