It didn't take long before the famous monks of the Shaolin Temple began using these shi shuo (("stone locks") to hone their strength and skills, and since then, generations have trained with them.
The practice of using these padlocks as workout equipment eventually made its way to Okinawa, where the locks were called ishi-sashi ("awesome stone locks") and used as Karate training tools. Today, in Asia, you can still find practitioners honing their stone lock skills and showing off amazing feats of strength and coordination in competitions and demonstrations.
Shi shuo aren't nearly as popular or ubiquitous as kettlebells -- yet. But aside from the difference in shapes, they're very, very similar. From a real-world, practical standpoint, there's no difference between the two: Both are heavy weights with an integrated lateral grip that's elevated above the weight's center of gravity. I can't think of any kettlebell exercises that you can't also perform with a stone lock. And the majority of stone padlocks vary in weight from about ten to thirty-five kilograms, which is about the same for most kettlebells.
There is, however, one key element to stone lock training that you don’t see much of in kettlebell work (with few exceptions): THROWING.
One book on Shaolin training methods explains that you should “[t]ry to achieve the stone padlock to fly up and rotate round its axis in the air, making…two or three revolutions, then catch it.” Eventually, you’ll be “able to control the number of revolutions [and] increase or decrease their number (revolutions) by will.”
This stuff looks insane.
If you're in the market for something a little different, and you've always wanted to toss around a big heavy rock with a handle, you may want to buy yourself a set of stone locks. Who knows? With any luck, maybe you'll be the Pavel of shi shuo.