Inspired by the the Sai, a traditional Okinawan melee weapon, the UPK-D1 Pocket Sai is a modern implementation optimized for compact and safe carry. This is not far from actual Sai history where Sai could be concealed within the loose fitting clothing of the time, the Kimono, and carried in sets of 2 or 3, of which various 2 handed and throwing techniques were used.
The UPK-D1 Pocket Sai is designed to collapse and cover the 'Saki' or Sai tip, when unlocked with the press of a button located on the motto (center of the Sai), the handle slides to eclipse the monouchi (main blade) and create an integral sheath when closed . This makes each Sai a contained solution with no need to return it to an accessory sheath. In its closed form, the Pocket Sai offers a formidable blunt striking weapon weighing about half a pound of hardened martensitic Stainless Steel.
I designed the Pocket Sai with faceted bevels along its blade to give it the intentionally ominous appearance. The best defense is a strong deterrent, as being forced into a confrontation only guarantees someone harm. With practice the Pocket Sai can be deployed with confidence and give any would be attacker a moment to reconsider their odds. Just as with any tool, it can only be effective as the user's training and preparation. With the "traditional" unsharpened version of the Sai, if need be, the point is very effective at penetration.
The Traditional Sai is not a sharp edged weapon, and most formal practices focus on defense manipulations to control an opponent's weapon and delivery of blunt strikes. The beveled mounuchi opens the option to fully form and grind the bevels to create a hand ground double edged dagger for those seeking it.
The Yoku, or side prongs are arguably the most recognized feature set of the Sai, and a significant effector in practical applications. Martial art techniques utilize the Yoku to offer opponent weapon control and highly effective pinch, hold, and puncture techniques.