Paratroopers jump with issued weapons, liked or despised. During D-Day U.S. troopers jumped with everything from the full-sized M1 Garand to the M1 Carbine and Thompson SMG. The German Fallschirmjager leaped into combat with K98k rifles, FG42 and MP40.
But what weapons armed the Imperial Japanese paratroopers that jumped into battle over Asia? Like many nations, Japanese small arms designers modified existing weapons to create the TERA series. TERA weapons were a class of Japanese rifle and submachine gun that could be broken down or collapsed to enhance portability.
The two best examples of TERA weapons with the Type 2 bolt action break-down rifle and the Type 100 submachine gun. It's believed by some the Japanese began a real push into airborne specialized weapons after their first combat drop on the Dutch East Indies in 1942.
During that operation Japanese paratroopers arrived at the drop zone separately from their canistered weapons and that separation, including canisters lost to swamps, realigned Imperial Japanese thinking on jumpable small arms.
The Type 2 was a derivative of the full-sized Type 99 Arisaka rifle. Chambered in 7.7mm the Arisaka was the starting point for the Type 2 rifle that would be deployed by the Teishin (Army special forces) and Rikusentai (marine paratroopers.)
The first version of the bolt action Japanese paratrooper rifle was built on a threaded barrel extension that would screw into the receiver assembly. However, the Japanese went in a different direction with a notch and wedge to join the forearm assembly and the receiver.
By joining the forearm/barrel assembly into the receiver a paratrooper could quickly twist into place the wedge located on the rifle's right side.
While a full-power rifle was standard for Imperial paratroopers, submachine gun technology lagged behind (an interesting comparison to Allied strategists to whom submachine guns seemed natural armaments of the airborne
Where the Type 2 was a two piece break-down rifle, the Type 100 was a wood stocked SMG that was cut and hinged at the back of the receiver. This simple move allowed the creation of a folding stock version of a standard rigid stock 8mm weapon.
Touches unusual to the Japanese SMG, compared to their enemies small-arms designs, was the addition of a bayonet and bipod. A smart and important internal modification was a chromed bore.
Knowing the tropical battlefields of the Pacific are the rust inducing enemies of small-arms, the chrome bore helped prevent this weapon jamming syndrome (a lesson the U.S. neglected to remember when issuing the first generation of un-chromed M-16s.)