For this class of weapon we have an ambivalence of terminology. The rather clumsy term of “Ball and Chain” is possibly the most accurately descriptive. “Morning Star” or “Morning Star Mace” is another term commonly used but this is also applied to some forms of non-articulated club. The term flail can be used for a “Ball and Chain” although to some this only suggests the sort of weapon made from two lengths of wood joined by a hinge. This latter class of weapons are sometimes termed “Bar flails”.
Flexible weapons such as the flail have several advantages over more rigid weapons. The first is that the end can be swung at a greater velocity, offering a faster strike with considerably more momentum. Both the knight and the common footsoldier found that the flail was a very effective device for unhorsing a mounted enemy. Flails were also difficult weapons to defend against since the head could curve over the top of a shield or weapon to strike the man behind. Chain flails also could be made to wrap around an enemy’s limb or weapon, disarming him or pulling him off balance.
This class of weapon can be subdivided into several parts. Most well known is the Ball and Chain type weapon most commonly associated with the medieval knight, although in the west it appears to have remained in use up to the 18th century. This weapon has a relatively short handle and one or more chains with weighted ends. Some models have an enlarged link or ring as the final part of the chain.
Most well known of the bar-flail type weapons is the Numchukas, which is essentially the agricultural tool used for flailing rice throughout the orient. Many bar-flails have distinct striking and handle sections and on many the handle may be of staff proportions, creating a weapon of polearm dimensions. These weapons are very similar in form and size to the tools used for threshing wheat in western agriculture. Such weapons are also found in China, though I don’t know if these originated in the north of china where wheat growing is more common. In the west the striking section (termed a “swingle”) was often enhanced with spikes or bands of iron. Another feature encountered was a hook between swingle and shaft to prevent it swinging about when not needed. Long handled bar-flails were a foot-soldier’s weapon and seem to be more commonly used by common soldiers and peasants than knights.
The Chinese three-Section staff can be regarded as a relative of the long shafted bar-flails.
A flexible weapon of note is the Japanese chigiriki. This resembles the ball and chain mace used in other cultures but differs in both the handle and the chain are at least two and a half feet long each. These increased dimensions offer some interesting capabilities. The weapon can be used single handed but a two handed grip is likely to be more common. The handle is essentially a short staff or Jo and can be used for various offensive and defensive jo-jitsu techniques. A pointed ferrule or spear-point placed at the butt of the shaft would seem to be a useful addition, but I have no evidence that this has ever been attempted.
As well as being swung in a conventional manner several other techniques are known to have been used with this weapon. The length of chain is sufficient that the weight can be taken in the hand and thrown directly at a foe like a rock. Alternately the weight can be twirled like a bolas/lasso and cast at an enemy. Both these techniques cause the weight to travel in a line rather than an arc. By co-ordinating such attacks with footwork and position of the handle a target several metres away from the fighter can be hit. By a sharp pull on the chain the weight can be recovered for another attempt or alternate technique.
Another interesting technique is to grasp the chain and strike the enemy with the handle section of the weapon. This would be useful in a situation when it was undesirable for the weapon to entangle with a target. This might occur if fighting multiple opponents. It might also be a good strategy against a mounted opponent. The handle could be struck across both the horse’s forelegs then the weapon employed conventionally against the thrown rider.
Some forms of kusarigama can be regarded as flails with blades added. Serge Mol’s “Classical Weapons of Japan” shows an example with a stabbing point in addition to the side (kama) blade.The Books