History:  Tools with a similar shape to the Yamanni-ryu Sai (Trident or Short Sword) include a hoe used to dig a furrow for planting rice or vegetable seed, and a variety of small pitchfork.  It is likely, however, that the Sai is a direct weapon import from China or Indonesia.

The photo above (omitted) shows two antique sai (on the left) and one modern mass-produced sai for comparison.  The older sai are both over 100 years old from China.  The sai on the far left is a forged iron weapon with an octagon bar and a grooved flat tip.  The horns are rounded and fitted to the central rod.  The handle is turned wood with metal fittings like a sword.  The pommel is a solid iron cube with the corners cut off.  The sai in the middle is a black forged wrought iron weapon.  Unlike the other sai the hammer marks are visible.  It was made without the use of a file and relied on the skill of the blacksmith to provide it with a final form.  Like the other sai it has a blunt tip and a nutcracker pommel.  The points of the horns are sharp.  The modern sai is lighter in weight, has a longer handle and the horns are wider with a different shape.  The original sai are balanced like a sword with the balance point about 2 inches forward of the guard.   Many modern sai balance at the cross point of the horns and the handle.

Description:  The Yamanni-ryu Sai resembles a trident with a central round or octagonal metal blade, which tapers slightly toward the tip, and two prongs or wrist guards on either side.  The round blades resist chipping better than the octagon ones.  However, the octagon blade does more damage on impact because the striking area is more concentrated.  The central blade in modern times is 15 to 21 ½ inches in overall length, and should be slightly longer than the user’s forearm when held in a reverse position.  The modern version is chrome plated steel weighing up to 3 pounds.   The handle is wrapped, traditionally with thin rope, or in modern times with some form of thick tape.  The butt end of the handle is designed for striking.  The tip is generally blunted.

2 TSUKA – Grip
3 MOTO – Wing Base
4 YOKU – Wing
5 TSUME – Wing Tip
6 MONOUCHI – Shaft
7 SAKI – Tip

Technique:  Even though sai are sometimes called “short swords”, they were not used as a traditional sword but primarily as defensive weapons.   They were used more as a club would be, but in pairs.  The sai can be used to block, stab, slash, punch, trap or even throw.  It was common practice to carry a third sai to replace one that was dropped or thrown.   When thrown the goal was to knock a rider off their horse, not by stabbing them, but more by the sheer surprise and weight of the sai.
Legend states that a strap of some sort was occasionally tied to the handle for retrieval.  Flipping the long end out, you effectively have a whipping, striking tool.  The long end could also be used for poking and blocking techniques.  The pummel on the Sai’s handle could be used to block and to punch and crush (i.e. skull).  A sai could also be attached to a Bo to create a spear.  In most styles the sai should be long enough to cover the forearm to augment blocking techniques.   The hand guards effectively protect the hands from damage and are also used to catch a strike from a weapon like a bo.  The prongs of the sai are good for blocking, catching and trapping bo or sword strikes.  Once the prongs complete the trap, the defender can use the sai to twist the attacker’s weapon from their grasp or even breaking the opponent’s weapon.  Because of the flipping techniques employed in use of the sai, strong and limber shoulders, arms, and wrists need to be developed if one is going to master their use.  For this reason, the sai has been a sought out addition to many karateka’s supplementary training for strength and coordination.  The efficient use of the weapon is much reliant on the dexterity of the practitioner with his thumbs, which the tang is balanced and rotated on along with the loosening and tightening of the grip from the small finger for striking and consolidating power.  Sai is the practice of  ‘Shuto’ in empty hand and emphasizes the need for ‘Koshi no Chikara’ (Hip power) and ‘Suri Ashi’ (sliding movement).  The importance of body movement and good footwork is ever more apparent as the weapon is of a smaller classification than Bo.  Advanced practitioners must learn to throw the Sai, a difficult requirement in view of the weight.  The Sai explores the weakness of Bo, thus making Bo-jutsu stronger.
The basic holding manner ‘Honte-Mochi’ (Natural) and ‘Gyakute-Mochi’ (Reverse) is prevalent with basic Sai whereupon the advancement to ‘Toku-Mochi’ (special grip) is introduced.  This brings the usage and actions of the Sai into the same family as Tonfa and Kama.

Yamanni-ryu Sai Kata

1) Shimabukuro no Sai Ichi
2) Shimabukuro no Sai Ni

3) Nakandakari no Sai
4) Kyan no Sai

5) Kishaba no Sai Sho
6) Kishaba no Sai Dai