Invented in the 14th century, the kotatsu has been trapping people with its warmth ever since. Forget all plans for a productive day once you turn onInvented in the 14th century, the kotatsu has been trapping people with its warmth ever since. Forget all plans for a productive day once you turn onInvented in the 14th century, the kotatsu has been trapping people with its warmth ever since. Forget all plans for a productive day once you turn on