
It's called Haramaki. It's basically underwear that you wrap around your waist. (sorry it's not explicit with this pic)
This was an old way to get yourself warm - when building heating system wasn't good. Back then, people used to put on anything they could to keep them warm.
Now that we are in the modern society, we thought we didn't need it any more because it's not sexy and we've got whole bunch of cool ways to warm ourselves.
But then, it's back! And it's back with whole new look. (see the website I linked below)
My sister said it was super warm.
And it is! I think it is back because people decided, after all, that this is much more efficient and comfortable than its modern version competitors!
....this is hard to explain. Can you imagine how much such a small piece of fabric can do to your body? It's pretty thin and fits your body, and when your tummy is kept warm, your whole body feels so much warmer!
If you are trying to minimize your expense, this small cloths can save your some dollars because you can lower the temperature of your home heater 2-3 degrees! And obivously it'll reduce your carbon footprint. I am serious.
Well, honestly, you can't wear your hip-hung jeans with this, but if you are done with that phase, it's for you. I found some interesting story on Haramaki: Check this out.