The Ball Bearing Dao 滚珠刀 of the Ming and Qing Dynasties

There is a very interesting and rare design element that appears in Ming and Early Qing Dynasty Dao, requiring expert skill and engineering to forge. At a time where swords were worn less on the battlefield and more in public as decoration, the rich and political elite saw to parading their wealth on their hilts by commissioning lavish decorations, precious metal gilding, and elaborate engravings. One impressive feat of craftsmanship was not on the hilt, nor on the scabbard, but on the blade itself. In the long grooves (fuller/bohi) a ball bearing or multiple ball bearings were encased and free to slide as the sword moved with a sound that many found appealing.

Not only was this incredibly difficult to forge, but it came at an expense as the addition of ball bearings did not improve the capabilities of the sword, but often times reduced it. The deep groove reduced the structure of the blade for taking impact making it prone to deformation upon impact, and were difficult to clean which resulted in rust and corrosion.

This trend of embedded ball bearings was not exclusive to sabers and could also be found in wooden furniture, jade, and ceramics. However, the appearance of ball-bearing sabers faded out around the mid-Qing Dynasty.

Pictures and information came from the book: “Swords Clash—Light Weapons on Chinese Battlefields Over the Past Five Hundred Years”
Additional photos from bilibili.