http://savoryjapan.com/wordpress/2011/09/takana-japanese-mustard-green-onigiri-recipe/
Kotatsu is a heater that is installed under a table top; the table’s covered with a blanket, and the system heats your feet. With the coming climate crisis and total social collapse, keeping your toes warm won’t be a priority, but after the collapse, you may want to have one of these, low-energy heating systems.