Type 98 was the most popular light AA gun of IJA. About 80% of IJA light AA guns were Type 98. It first saw action in Nomonhan and it was used until the end of WWII.
Type 2 was newly designed referring to the German 20mm Flak. The barrel of Type 2 could be elavated over 90 degrees. A central fire-control system was developed for Type 2. It could control 6 cannons at same time by a remote control device.
20mm Twin AA Machine Cannon was equipped with two guns of Type 2 20mm AA.
Type 4 20mm Twin AA Machine Cannon was equipped with two guns of Type 98 20mm AA. It was introduced in 1944 and approx. 500 guns were produced.
This is an infanty AA weapon similar to infantry mortar. It shoots off the shell and the shell discharges 7 small mines with parachute in the air. The mines explode in the air and damage close aircrafts.
There existed two kinds of AA Mine Discharger, 7cm and 8cm caliber. Maximum altitude is about 600 m.