This is pretty interesting. It's hard to tell from the video exactly how to do it. Looks like it'll take a lot of practice. I wonder if there's anywhere else where you can apply spins similar to table tennis and the like.
It's a crappy video, not sure why they chose that specific one. Here is a better one: https://www.youtube.com/watch?v=n_QyPCCxriQ
TLDW: Use your thumb and forefinger in a flicking motion to add a large amount of spin to the cork so that it rotates very fast with the feathers pointed up during rotation, like a top. While it is spinning like a top in midair, make contact with the racquet, but not too hard. The initial contact to send the shuttlecock over the net turns it upside down (cork points to the sky).
The rotational motion that you added (with the flick) to the shuttlecock adds gyroscopic stability, like the rifling on a gun, which keeps the shuttlecock upside-down for longer. When the shuttlecock gets over the net, the cork is still pointing to the sky which makes it impossible to return because the racquet can now only make contact with the cork in a downward position.
In normal flight/serve, the cork is pointing to the floor when the shuttlecock gets over the net, so it can be given some lift when returning.
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[1] It also doesn't help that the camera view of badminton matches is not from the side, so you can't really see how hard this is to return even in slow motion.
"yes, it does work"
On a feathered shuttlecock, the feathers aren't symmetric; they overlap in one direction.
Might be possible on a plastic shuttlecock, though.
To make sure you don't apply spin, you have to toss the ball with open palm.
Of course, once the racquet hits the ball, spin is a huge component of the game, and a big aspect of what makes the game so interesting and complex.
Albeit ime this is something even kids do, not sure why it is "new"?
Edit: I may be referring to the Sidek serve it was based on
From reddit (also not 100% sure):
The sidek serve is an other technique and has been banned for some decades (not 100% sure, but the spinning effect was caused by hitting the feathers first , I think), whereas the new spinning serve resulted from spinning the shuttle with the fingers before hitting the cork.
https://old.reddit.com/r/badminton/comments/1e18zys/comment/...
The Sidek family was a dominant badminton force for Malaysia during that period. [1]