Wednesday, January 09, 2013

Unlucky at cards ...

I thought that I would try shuffling cards with my hands reversed. After all, if I could make a complete hash of doing it right-handed, going all sinister could hardly make things worse, right?

I was quickly disabused of this notion, both by my wife, who keeps a sceptical eye on my misguided attempts, and by my useless hands failing to do what I intended.

There are several different ways to shuffle a set of cards. I'm starting on with an righthanded overhand shuffle; the pack is held in the left hand, long edges perpedicular to your chest, cradled against the fingers and held stable with the thumb. You then pick a wedge of cards from the bottom of the deck with your right hand, gripping the short edges with your thumb (closest to you) and the tips of your fingers (at the far end).

To mix the cards you then throw them from your right hand into your left; random cards should move from the back of the pack to the front.

The devil is in the details. If you don't apply enough pressure with your left thumb on the remaining cards, then the pack gets unstable and can fly apart. Too much pressure, and you'll struggle to transfer cards smoothly from your right hand back to your left. However, varying pressure with your thumb allows you to make the shuffle more complicated, as instead of just pushing cards from right to left, you can pull the front of the deck back with your right hand, and then use your left thumb to grip onto the cards and retain some of them, before putting more from the cards in your right hand into your left.

This is better displayed with a diagram or video, than just with verbiage, but until my camera operator comes back from the pub, that's all we have to deal with.
Because you need to have fine motor skills to shuffle a pack of cards cleanly, it's the sort of thing it's probably quite hard to get a robot to do. (Mechanical card shuffling devices are another kettle of fish, although if you use a fish kettle to randomise playing card selection, you're doing something extra special and well beyond the scope of this.)

The particular cards you use will make a difference too. I've got two decks, one smaller and smoother than the other; the larger, plastic coated deck is noticeably harder to perform this shuffle on. There's lots of different ways to make things hard for yourself.

It's also quite hard to get your hands to do it if you attempt a lefthanded overhand shuffle, changing to use your less dextrous hand to grip the cards you're removing from the back of the deck and replacing at the front. Just as the thumb on the receiving hand needs a particular amount of grip, so the grip on the throwing hand needs to be enough to keep the pack together, but loose enough to allow them to slide into the receiving hand smoothly.

Slow is smooth, and smooth is fast. Don't forget that, otherwise it becomes a real mess when learning these things. It's more difficult to move the cards around very slowly (something to do with static friction, perhaps, or needing to be dynamic enough with wrist movements to get the cards to move in straight lines?) so another challenge is to go quickly enough to get the cards to move neatly, without sacrificing proper form.

Still, my left handed shuffle has improved markedly from my attempt this morning. Neither left nor right is particularly wonderful yet, but they're both leaps and bounds better than when we started.


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