These thread balls are called Temari. China introduced them to Japan in the late 7th century. They were originally used by children of the wealthy noble class in a Japanese variation of hacky sack called, kemari. The game became increasingly popular over time and mothers and grandmothers, who could not afford to buy their children the foreign imports began to make their own. They would use remnants of old kimonos and wrap them in the salvaged thread.

As time went the balls' stitching started to become less functional and more decorative until the balls evolved into the art form they are today. Which I think is a pretty cool thing. I use to have a bunch when I lived in Asia and would string them up like they do in the small photo above and turned them into kick-ass Christmas ornaments. However, now that all seems absurd and would cost a small fortune. I tried finding them stateside and they go for around $50 a piece. Um what? I should have stocked up while I was still living far east.
All the large photos of the Temari balls are via NanaAkua.