Source: Classical literature
In Manchu, kuhen means:
1. a large blood vessel in the belly of livestock that is attached to the spine
2. in traditional Chinese anatomy, a vessel along the spine that was thought to nourish the five vital organs
3. grooves on a knife, sword, or arrowhead
4. sprouts on a tree 1
In the Tongwen Guanghui Quanshu (同文廣彚全書) of 1704 it features in the arms section as being translated into Chinese as dāo cáo (刀槽) or "saber groove." 2
Such grooves are often erroneously called "blood grooves", but their real purpose is to improve on the saber's handling characteristics by reducing weight in certain areas while retaining much stiffness.
The use of grooves also provided the bladesmith with an opportunity to add complexity to the aesthetics of the saber blade. At the height of Chinese saber making in the late Ming to mid-Qing dynasty, we see great variety in the combination of grooves, bevels, and dimples used for this purpose.
Chinese bladesmiths took much inspiration from the sabers of the steppe, as well as Japanese, Persian, and Indian design features.
For a complete overview of saber terminology, see: A Chinese saber glossary.
Classic configuration of saber grooves on a 17th century Chinese saber.
Double grooves, dimples and long backedge on a mid-Qing dynasty saber.
A configuration featuring segmented grooves on an 18th century Chinese saber.
Japanese naginata-inspired grooves on a 17th - early 18th century Chinese saber.
Persian inspired U-turn grooves on a 17th century Chinese saber.
Triple grooves featuring a U-turn at the forte, combined with a long back bevel on an 18th-century presentation saber.
1. Jerry Norman; Concise Manchu-English Lexicon, University of Washington Press, Seattle, 1978.
2. Tongwen Guanghui Quanshu (同文廣彚全書) or "Enlarged and complete dictionary" of 1704. A Qing imperial dictionary in Chinese and Manchu, each entry double-checked and approved by the Kangxi emperor.